Joyce shouted something I couldn’t make out over the drums that were pounding in my ears. I jerked away from the cot that was half-supporting my weight, staggering toward the dubious safety of the wall, where at least no one would grab me. My father was bellowing for security—and that was something I understood perfectly well. He was so loud that I could hear him even through the screams, even through the endless sound of drums.

Someone grabbed my arm.

I screamed and tried to jerk away, only to have the intern who was holding me pull me roughly back, away from the sea of agitated patients. “Ms. Mitchell, please! Calm down!” he said, continuing to pull. “We need to lock this room down, and that means all civilians need to be removed.”

I was too shaken to speak, and so I just nodded, trying to force myself to breathe as I let him lead me toward the door. I glanced back. Joyce was being escorted away from the floor by another intern, and our father was still in the middle of it all, trying to pry Ms. Lawrence’s fingers off Dr. Snyder’s throat. Dr. Snyder was barely twitching as she hung limply, half supported by my father, half by the gnarled hand of the parasite-infected old woman who was crushing the life from her.

Is this what you wanted, Dr. Cale? I thought, as the sound of drums got louder and the scene started to take on a strangely unreal quality, like I was seeing it through gauze. Is this where the broken doors were supposed to lead us? There are only monsters here…

Then, as calmly as if he were waking up in his own bed at home, one of the patients sat up. The restraints that were meant to hold him down fell away as he moved, split cleanly down the middle. Either the fabric of the belts had been frayed by the stress of his constant squirming, or his body’s new driver didn’t know yet about the breaking point of flesh and bone—it wasn’t playing gently with its toys. His eyes rolled madly in his head, jaws working as he turned toward us and slid to his feet.

Someone hit an alarm. Red lights began to flash as a siren blared from hidden speakers, alerting the entire building to a breach in the medical holding area. The intern gave me another jerk, away from the man who was now advancing toward us.

“Aren’t you supposed to be armed?” I demanded. “You’re the army!”

“Ma’am, I’m not even a doctor yet! They didn’t give me a gun!” He dropped my arm. “Run!”

I turned when he did, and I ran, following him toward the nearest door. One of the flashing red lights was above it, and I saw white, terrified faces through the door’s narrow window, looking back at us from their place of safety. Then the security slammed down, the door sealing with a loud bang that sounded like every deadbolt in the world being thrown, and we were trapped.

I turned to the intern, blindly hoping he could tell me what to do, but he was already running for the corner, leaving me standing on my own. I stared after him for a few seconds—too long—before spinning and flattening my back against the door, hoping that the people on the other side would take pity and open it for me. I’d take falling on my ass over having my neck broken any day.

What I saw when I turned back to the room was a horror show. The red lights flashing overhead didn’t help; they painted the whole scene bloody, making it look like we were in the middle of a slaughter. And then the jerkily moving sleepwalker somehow caught up to the first of the interns—and how could he move so fast, he wasn’t used to having a body, he shouldn’t have known how to make it work so well, he shouldn’t have been so fast—and grabbed her by the shoulders, burying his teeth in her throat. She screamed, a high, shrill sound that somehow rose above the alarms for a single horrifying second before it stopped as abruptly as it had started, cut off by the severing of her trachea. The cessation of the sound should have seemed like a mercy. Would have seemed like a mercy, even, if it hadn’t been followed by the sudden red gush of arterial blood that poured from the wound his teeth had made.

As for the sleepwalker, he stood there for a few moments, swaying, clutching the twitching, half-dead intern like a teddy bear. Then his arms unlocked, and she fell limply to the ground as he straightened and looked around the room for another target.

The drums were pounding in my ears again. I pressed myself harder against the closed door, praying that his gaze wouldn’t fall on me. Please don’t see me, I thought. Please, please don’t see me. I’m sorry I kept secrets from my father. I’m sorry I didn’t tell him everything Dr. Cale told me. I’m sorry I’m sorry I’m sorry…

The swaying sleepwalker’s gaze fell on me, a sudden sharpness coming into his eyes. I swallowed, glancing frantically around for a place to run. Ms. Lawrence was still latched onto Dr. Snyder’s throat. Dad was no longer trying to pry her loose. Instead, he had pulled the gun from his belt and backed away two steps, taking careful aim on the seemingly frail old woman with the unbreakable grip.

I wanted to look away when he pulled the trigger.

I couldn’t.

Ms. Lawrence collapsed in a bloody heap, just like the intern whose throat had been ripped out by the man who was now advancing on my position. Dr. Snyder collapsed as well, crumpling to the floor. My father, with his first and most immediate crisis handled, turned to scan the room. I wasn’t screaming; he didn’t know where I was, and he had two daughters to worry about, not just one. So maybe it shouldn’t have felt like such a betrayal when he turned away from me, scanning the far side of the room for Joyce before he did anything else.