Grunt: The Curious Science of Humans at War

by Mary Roach

  Segall was born a Stuart, but on his movie credits and in my mind he is always and very much a Stu.* Chest hair can be seen, and some necklace in there. There are whiskers, sparse and longish, somewhere between beard and I-don’t-feel-like-shaving. He has a wife but spends more time in the company of Bob, an agreeable Rottweiler who naps on the black leather couch in his office. Segall dives in and out of careers with glee. Writing, directing, producing (most recognizably, the TV crime drama Hunter). He owns a diner next to the studio. He doesn’t cook, but occasionally he names menu items, and you can pick them out without too much trouble—for example, the Boob (chicken breast) Sandwich.

  Early in 2002, with Hollywood’s appetite for action dramas dampened by the events of 9/11, Segall began repurposing his talent for gore and violence. He founded a company, Strategic Operations, to produce loud, stressful, hyper-realistic (the coinage has been trademarked) combat simulations for training military personnel: the fog of war, in a box. Many of the trainees are corpsmen (Navy medics who deploy with Marines and SEALs)—men and women whose job may require them to perform emergency procedures while guns are going off around them and people are screaming and dying and bleeding like garden hoses. The underlying concept is “stress inoculation.” If you’re thrown into a staged ambush in Stu Segall’s Afghan village mock-up, the thinking goes, you’ll be calmer and better prepared when the real shit hits overseas. For medics, being calmer matters a lot. The fight-or-flight response is helpful if you’re fighting or taking flight but, as we’ll see, fairly catastrophic if you’re trying to stanch the flow of blood from an artery or cut an emergency airway or just generally think fast and clearly.

  Forty future corpsmen for the 1st Marine Division, headquartered in nearby Camp Pendleton, are here today as part of a combat trauma management course. Over the course of two and a half days, the trainees will administer pretend emergency care to role-players, most of them Marines, in six varieties of military pandemonium, beginning with an 8:00 a.m. insurgent attack in the Afghan village.

  The village, the largest of Segall’s sets, consists of two dozen ersatz mud-brick buildings, a small market, a rusting swing set, and, until recently, goats. (The goats were dismissed, because someone had to come in over the weekend to feed them, and more often than not it was Segall.) To get close to the action, I requested a role. I will be playing myself: a reporter who gets in the way and distracts people from their jobs. They’ve placed me in a sparsely furnished two-room house with a seasoned medical role-player named Caezar Garcia.

  Under a torn pant leg, Caezar wears a simulated skin sleeve—silicone encrusted with mock gore and plaster bone fragments. A simulated severed artery will bleed via a small pump connected to three liters of house-brand special effects blood that Caezar wears in a concealed backpack, a sort of CamelBak for vampires. The flow is controlled by a wireless remote, so it can be stopped or slowed or allowed to continue unabated, depending on how competently the corpsman has placed the tourniquet. Originally the instructors, who hover on the fringes of the action during scenarios, held the remotes. Caezar, wanting a more nuanced bleed, petitioned to control it himself.

  “I said, ‘Look, once you bleed me out—’” Caezar stops to listen. The call to prayer has started. The recording, being played over a set of speakers on a tower at the center of the village, is the signal for the role-players and the pyrotechnics guy to take their places. Through a window to our left, the trainees can be seen entering the village. They walk in formation, armed and armored, looking unrelaxed. The tape-recorder muezzin finishes his call, and for a moment it’s quiet. I can hear the soft, plasticky thrum of Caezar’s blood pump.

  And then I can’t. First comes the familiar high whistle of an explosive-powered projectile, a sound that, depending on your life experience, presages pretty lights in the summer sky or a rocket-propelled grenade explosion. Rifle fire follows. The ammo is blanks, but you wouldn’t necessarily know that, because the pyrotechnics guy sets off an accompanying “dust hit” on the ground or wall.

  The muezzin’s voice has been replaced by a recording of whizzing, ricocheting bullet noises and panicked soldiers yelling. It sounds like it was a hell of a battle. (I asked Segall about it later. “Vietnam?” “Saving Private Ryan.”) You wonder what they make of it over at the Water Authority.

  “OOOOOH, FUCK! AAAAAAOHH HELP ME!” That’s Caezar. He’s very good.

  A trainee steps into the room. His gaze drops to the floor, to a foot, in a boot, nowhere near a leg. Bone and mangled flesh—the remnants of a lower leg, sculpted by “wound artists” working from photos of a real injury—protrude from the boot. The corpsman blurts out, “Are you okay?”

  Years ago, crossing a street with my friend Clark, we looked down to see a smear of blood and feathers marginally recognizable as a pigeon. Clark bent over and yelled, “Are you okay?” The line is less funny now but equally ludicrous. A small blood lake expands on the floor. And here is where things go hyper-realistic: Unbeknownst to this corpsman, Caezar is an amputee.† He wears the silicone sleeve over the stump of his leg. When he jerks it around, as he is doing now, it trails an arc of blood. Blood is flying like champagne in the locker room after the big win.

  Outside the door, instructors are yelling to get the other wounded “off the X”—out of sight, out of the kill zone. They’re dragged into the room adjoining ours. The floor is men: role-players on their backs and trainee corpsmen crouched around them. One figure stands out for being unusually barrel-chested. This is the Cut Suit actor. You may be familiar with “patient simulators” like Resusci Anne, upon whom first responders practice their skills. The Strategic Operations Cut Suit is a “human-worn” patient simulator. The actor dons a vestlike rib cage with an insert tray of abdominal organs and, over this, a kind of flesh-tone wetsuit—simulated skin that bleeds when it’s pierced, via the same pump-and-tube system Caezar uses for his stump. (It also “heals,” with help from the Cut Suit Silicone Repair Kit.) It’s as though someone crawled inside Resusci Anne and gave her the one thing patient simulators, for all their bells and whistles, will never have: humanity. SimMan may bleed and pee and convulse, his tongue may swell and his bowels may rumble, but he will never sit up, drill his gaze into a student’s eyes, and plead, as Caezar just did, “Get me out of here, this is a bad neighborhood, man!”

  Today’s Cut Suit actor isn’t yelling, because his character has been shot through the chest and his lung has collapsed. He takes shallow panicky breaths while a trainee, whose uniform identifies him as Baker, gets ready to do a needle decompression. When a bullet or broken rib punctures a lung, inhaled air begins to fill the cavity that houses the lung. The air builds up and soon the lung can’t expand, and breathing becomes a struggle. It’s called pneumothorax, from the Greek for air and chest, and it is the second most common cause of combat death. Baker’s task is to insert a needle catheter to release the air and relieve the pressure. He’s sweating. His glasses slide down his nose. He holds the needle near the role-player’s collarbone, which is not between any of his ribs, or even part of the Cut Suit.

  “Are you FUCKING SERIOUS, BAKER?” You know the exaggerated TV cliché of the scary yelling Marine instructor? It’s not exaggerated. “That’s his clavicle. You almost actually stabbed him.”

  Presently the needle finds its mark, an occlusive bandage is applied, and the role-player is loaded onto a stretcher. Baker picks up the stretcher’s front handles without alerting the trainee at the other end, causing the patient and the $57,000 Cut Suit to tumble onto the ground.

  “What the fuck is wrong with you, Baker?!”

  Nothing, in fact. Just his sympathetic nervous system doing its job. Anything perceived as a threat trips the amygdala—the brain’s hand-wringing sentry—to set in motion the biochemical cascade known as the fight-or-flight response. Bruce Siddle, who consults in this area and sits on the board of Strategic Operations, prefers the term “survival stress response.” Whatever you wish to call it, here is a nice,
concise summary, courtesy of Siddle: “You become fast, strong, and dumb.” Our hardwired survival strategy evolved back when threats took the form of man-eating mammals, when hurling a rock superhumanly hard or climbing a tree superhumanly fast gave you the edge that might keep you alive. A burst of adrenaline prompts a cortisol dump to the bloodstream. The cortisol sends the lungs into overdrive to bring in more oxygen, and the heart rate doubles or triples to deliver it more swiftly. Meanwhile the liver spews glucose, more fuel for the feats at hand. To get the goods where the body assumes they’re needed, blood vessels in the large muscles of the arms and legs dilate, while vessels serving lower-priority organs (the gut, for example, and the skin) constrict. The prefrontal cortex, a major blood guzzler, also gets rationed. Good-bye, reasoning and analysis. See you later, fine motor skills. None of that mattered much to early man. You don’t need to weigh your options in the face of a snarling predator, and you don’t have time. With the growing sophistication and miniaturization of medical equipment, however, it matters very much to a corpsman. Making things worse, the adrenaline that primes the muscles also enhances their nerve activity. It makes you tremble and shake. Add to this the motions and vibrations of a medevac flight, and you start to gain an appreciation for the military medic’s challenges.

  On top of caring for the wounded, corpsmen are expected to return fire if no one else is able. Like any precision task, marksmanship deteriorates in high-stress situations. The average police officer taking a qualifying test on a shooting range scores 85 to 92 percent, Siddle told me, but in actual firefights hits the target only 18 percent of the time.

  The corpsman trainee working on Caezar is having difficulty with the tourniquet. Like Baker, he’s a fine, fumbling example of the downside of an adrenaline rush. An instructor puts his head through the doorway. “What are we doing in here, fuckin’ organ transplant? Let’s go!”

  If the scenario were real, Caezar would be dead by now. With a large artery bleed, it can take less than two minutes for the human heart—and, no coincidence, the Strategic Operations Blood Pumping System—to hemorrhage three liters: a fatal loss. The human body holds five liters of blood, but with three gone, electrolyte balance falls gravely out of whack, and there’s not enough circulating oxygen to keep vital organs up and running. Hemorrhagic shock—“bleeding out”—is the most common cause of death in combat.

  This is the grim calculus of emergency trauma care. The more devastating the wounds, the less time there is to stabilize the patient. The less time there is and the graver the consequences, the more pressure medics are under—and the more likely they are to make mistakes. In a 2009 review of twenty-two studies on the effects of “stressful crises” in the operating room, surgeons’ performance was reliably compromised: not only their technical skills but their ability to make good decisions and communicate effectively. And the stressful crises of the operating room—defined in this study as bleeding, equipment malfunctions, distractions, and time pressure—are business as usual in a theater of war.

  Caezar exits the scene in a fireman carry, draped around a trainee’s neck like a heavy mink stole. Baker follows behind with the stretcher. He’s struggling because his palms are sweaty. He sets down his end in order to wipe his hands on his pants—again, without alerting the guy holding the other end.

  “Really, Baker?” Palm sweat is a feature of fight-or-flight thought to have evolved to improve one’s grip, but too much of it obviously has the opposite effect. “Put your fuckin’ little girl gloves on if you have to.”

  The instructors are mean for a reason. They aim to subject the trainees to as much fear and stress as they can without actually shooting at them. The entire experience—the mock injuries, the gunfire and explosion sounds, the anguish of being called a little girl in front of everyone—is meant to function as a sort of emotional vaccine. Combat training for all troops, not just medics, has traditionally included exposure to some kind of simulated gore and mayhem. For years, writes Colonel Ricardo Love in his 2011 paper “Psychological Resilience: Preparing Our Soldiers for War,” commanders have shown their charges photos and videos of gruesome injuries, or brought in veterans to talk about “the horrors they experienced.” To help prepare future corpsmen, the Naval Health Research Center hands out copies of The Docs, a 200-page comic book with lurid drawings of blast and gunshot injuries—a graphic graphic novel.

  The pyrotechnics and battle soundtrack not only add realism but also kick-start the fight-or-flight reaction. Sudden loud noise triggers a cluster of split-second protective reflexes known as the startle pattern. You blink to protect your eyes, while your upper body swivels toward the sound to assess the threat. The arms bend and retract to the chest, the shoulders hunch, and the knees bend, all of which combine to make you a smaller, less noticeable target. Snapping the limbs in tight to the torso may also serve to protect your vital innards.‡ You are your own human shield. Siddle says hunching may have evolved to protect the neck: a holdover from caveman days. “A big cat stalking prey will jump the last twenty feet and come down on the back and shoulders and bite through the neck.”

  This may lead you to wonder, do impalas and zebras exhibit the startle pattern? And you would not be first in wondering. In 1938, psychologist Carney Landis spent some time at the Bronx Zoological Park, testing the evolutionary reach of the startle pattern, and the patience of zoo staff. In exhibit after exhibit, Landis could be seen setting up his movie camera and firing a .32-caliber revolver into the air. Less unsettling for zoo visitors—and more entertaining—would have been the experimental technique of fellow startle response researcher Joshua Rosett, who snuck up behind his (human) subjects and flicked the outer edge of their ear with his index finger. I imagine it was a trying time for the Rosett family.

  The Bronx Zoo had no impalas, but they did have a goatlike Himalayan tahr, and it was duly startled. As was the two-toed sloth, the honey badger, the kinkajou, the dingo, the Tibetan bear, the jackal, and every other mammal that endured the scientific obnoxiousness of Carney Landis.

  You will not be startled to learn that Landis’s book-length treatment of the topic, The Startle Pattern, fell somewhat shy of runaway success.

  TODAY’S SECOND scenario is a simulation of the aftermath of an explosion on a Navy destroyer. I have a symptom this time: smoke inhalation burns, which entitles me to some lines and a perioral dusting of soot. The set comprises a room of sailors’ bunks, or “racks,” and a sick bay down the hall. Catwalks overhead allow instructors to observe the trainees and hurl down invective.

  The sight of smoke from a smoke machine is our cue to action. Five of us lie on racks in the dark, emoting amateurishly. I tell the trainee who comes to my aid that it hurts to breathe. He helps me out of my rack and steers me out to the hall. “Right this way, ma’am,” he keeps saying, as though my table awaits. He shouts ahead that I’m going to be the priority. “Ma’am, we’re going to have to crike you. Do you know that that means? We’re going to make a small incision right here.” He touches the front of my neck. Crike is short for cricothyrotomy. They’re going to pretend to cut an emergency airway for me to breathe through.

  “You are?” My symptoms only call for oxygen.

  “Yes, we are. Because you can’t breathe.” I’m lifted onto the sick bay exam table.

  “Well, it’s more that it hurts to breathe.” I’m trying to give a hint. “It burns.”

  The trainee picks up a scalpel. A voice sounds from above, like God calling to Abraham. “Stop!” It’s one of the instructors. “She’s talking to you, right? Then she’s breathing. She doesn’t need that.”

  Someone else yells, “Blood sweeps!” A corpsman trainee reaches under my back and slides both hands from shoulders to hips. He looks at his hands, checking for blood, for a wound that might have been overlooked. If you don’t happen to be wounded, blood sweeps feel lovely.

  My massage is short-lived. I’m carried back out to the hallway and set down beside another amputee actor, Megan Lock
ett. I saw Megan in the makeup room earlier. The special effects gore was still wet on her stump. She sat with her legs crossed, idly scrolling on her phone. It was like lions had come and gnawed off her foot while she checked Facebook.

  The floor is slick with blood. Megan is having a bleeder malfunction. A pair of trainees skid and slip, trying not to drop the latest priority victim, a man wearing a tourniquet on his lower leg where a sock garter, in more civilized circumstances, might go. They plop him down on the exam table.

  “And why is this guy so important?” yells God from on high.

  “Open fracture!” someone tries.

  “Is he dying? No, he’s not!” More loudly now: “Who’s dying, people? Who is the most likely to die?” No answer. God’s hand points at Megan. Megan raises her stump. Hello, boys! “What does this patient look like she has?”

  Two trainees rush over to get Megan, while Open Fracture joins me in the hallway of survivable maladies. I try to make some room, but my pants are sticking to the floor. I learn later that Karo syrup is the main ingredient in special effects blood. This makes life safer and more pleasant for actors whose role calls for them to cough up blood, but if it dries while you sit or stand in it, you will fuse to the floor like a candy apple on a baking tray.

  When it’s all over, the trainees are called to a debriefing on the pavement outside the set. An instructor named Cheech starts it off.

  “That was godawful. You lost your minds. A woman who’s missing a leg should have been the number one priority.”

  Excuses are offered. It was dark. Smoky. She was down on the floor.