"What have you done?"

I'm backed up against the wall close to the sealed door. My finger bones are digging into the concrete, tearing at the plaster. I stare with shock and disgust at the zom heads as they squat close to Mark's remains, licking their fingers clean, dipping them back inside his emptied skull in search of any last tidbits. They look happy, sated, full. They pay no attention to me. Like junkies after a fix. Spaced out. In a world of their own. A world of murder, cannibalism and sweet, sweet brains.

"Oh, God, what have you sick bastards done?" I moan, shaking my head, trying to close my eyes to the nightmare, praying for tears that will never come.

Tiberius glances at me and frowns. He gazes at Mark, then at his fingers. For a moment he looks like himself and he cringes. A look of regret and terror flickers across his face. Then his jaw tightens and I see him turn away from remorse. He gives himself over to the pleasure of the feed and zones out again.

Cathy is giggling. She pokes out one of Mark's eyes, the way I poked out Dr. Cerveris's earlier, and plays with it. She puts it in her mouth, sucks on it a while, then spits it up into the air and tries to catch it with her tongue as it drops. She misses. It hits her chin and bounces away. She giggles again.

Peder and Gokhan are still fishing for scraps of brain. Gokhan is muttering, "Innit. Innit. Innit." Peder nudges him aside, crouches over Mark like a dog and sticks his face into the cavity of the dead boy's head to lick out any last morsels.

"You're monsters," I sob. But they're not really. They're just hungry creatures who fed when prey was presented to them. I identify with the zom heads too closely to condemn them completely. I had to fight hard not to turn on Mark. If it had been five minutes later, or ten or thirty or however long I have left before my senses crumble, I would have joined in.

I could be harsh and say that they haven't regressed, they're still revitalizeds, they had a choice. But who am I to judge? I was able to fight temptation because I can naturally hold out longer or because I ate slightly more of Dr. Cerveris's brain than they did. Maybe they weren't able to resist the way I was.

Either way, I'm sure they'll feel guilty later, once the feeding frenzy passes and they recover their wits. They'll probably spend the rest of their conscious days regretting the way they gave in to their base instincts. That won't do poor Mark any good, but at least they'll suffer. I think they'll probably envy me once I lose my grip and regress. The only way they're ever going to escape the awful memory of their crime is by shedding their humanity entirely and becoming dumb reviveds again.

As I pause between moans, I hear a noise in one of the corridors. Footsteps. I tear my gaze away from the vile spectacle and watch sluggishly as Josh Massoglia enters the room, a small team of soldiers spreading out to flank him.

Two of the soldiers are carrying flamethrowers.

The zom heads pay no attention to the soldiers. Mark's brain was enough for them. They don't need any more at the moment. They don't even react when the pair with flamethrowers takes aim.

"Wait," Josh says. He's staring at me. My fingers are still scratching the wall. My head is shaking softly.

Josh crosses the room and stops in front of me. He looks at my fingers, my lips, then into my eyes. His right hand comes up slowly and stretches out towards the calculator on the screen. He keys in six numbers and it makes a beeping sound.

The door slides open.

Josh steps away from me and lowers his hand. He doesn't say anything. My fingers fall still. My head turns towards the open door. Bewildered, I look to Josh for confirmation, but he doesn't give me any signs.

I peel myself away from the wall and stumble through the doorway, into a corridor that rises like the one I was in before. I feel as if I'm in a dream, but I can't be. The dead don't sleep, so the dead can't dream.

The door starts to slide shut behind me. I step to the side, looking for Josh one last time, searching for answers. But all I see is a sudden blossoming of red and yellow flames.

There are agonized screams, the voices of four teenagers blending into one as the zom heads pay the ultimate price for turning on Mark. The stench of burning flesh, flames consuming all, both the monsters and their victim.

Then the door clicks shut and there's nothing.

Only me.

My cheeks are dry but I wipe a hand across them anyway, brushing away nonexistent tears. Then I turn and stagger up the corridor. I expect it to twist back on itself like the other one did, but this just keeps rising until it levels out into a tiny room. There's a plain wooden door in one of the walls, no scanners, locks or anything. I can smell the outside world, a rich, pungent, overwhelming scent after the clinical, carefully maintained atmosphere of the complex.

With a moan born more of confused dread than delight, I shuffle forward, push open the door, leave the nightmarish gloom of the underground behind me and step out into sunlight.

To be continued...