It goes very quiet in my head; I stand over the assembler terminal shivering, taking rapid shallow breaths. A shadow seems to have passed from my mind, leaving only a cautious peace behind. The horror I feel is hollow, now, an existential dread—So they hid zombie code inside me? Whoever they were? —but I'm back, I'm still me . I'm not going to suddenly stop existing, to be replaced by a smiling meat puppet wearing my body. It was just an escape package, configured to report home after a preset period or some level of stress if I couldn't figure out what to do. When it couldn't dial out, it issued a callback to me, the conscious cover, and told me what it wanted. Which is fine. If I do what it wants and escape, then I can get any other little passengers dug out of my skull and everything will be great! And I want to escape anyway, don't I? Don't I? Think happy thoughts.

"Fuck, I just killed Fiore," I whisper. "I've got to get out of here! What am I doing ?"

Upstairs, the common room is as steamy as a sauna. Coughing and choking I dial down the heat, grab my damp clothes, and pull them on, then head for the door. Then—this is the hardest part—I pat my hair into order, pick up my bag, and calmly walk across the front lot toward the curb to hail a passing taxi.

"Take me home," I tell the driver, teeth nearly chattering with fear.

Home, the house I've shared with Sam for long enough to make it feel like somewhere I know, is a scant five minutes away by taxi. It feels like it's halfway to the next star system. "Wait here," I tell the driver. I get out and head for the garage. I don't want to see Sam, I really hope he's at work—if he sees me, I might not be able to go through with this. Or even worse, he might get dragged in. But he's not around, and I manage to get into the garage and pick up my cordless hammer drill, a bunch of spare bits, and some other handy gadgets I laid aside against a rainy day. I go back to the taxi, and I'm still tightening the belt to hang everything off when it moves away.

We cruise up a residential street, low houses set back from the road behind white picket fences, separated by trees. It's hot outside, loud with the background creaking of arthropods. We drive into a tunnel entrance. I take a deep breath. "New orders. Stop right here and wait sixty seconds. Then drive through the tunnel and keep going. Keep your radio turned off. At each road intersection, pick a direction at random and keep driving. Do not stop, other than to avoid obstructions. Accept one thousand units of credit. Continue driving until my credit expires. Confirm." I bite my lower lip.

"Wait sixty seconds. Drive, turning randomly at each intersection, until credit limit exceeded. Avoid obstacles. Confirm?"

"Do it!" I say, then I open the door and pile out into the tunnel mouth with my kit. I wait tensely as the zombie drives off, then I start walking back into the blackness.

The tunnel darkens as it curves, and I pull the big metal flashlight out. Like everything else here, it's probably not authentic, no electrochemical batteries—the same infrastellar T-gate that powers cars or starships will suffice to provide a trickle of current to a white diode plate. Right now, that's good news. I shine it at the walls to either side as I walk, until I come to one of the recessed doors. Unlike the last time I came this way, I'm prepared for it. Out comes the hammer drill, and I only spend a few seconds sliding a stone bit into it—all that time in the garage has paid off, I guess. The racket it makes as it bites and chews at the concrete next to the door is deafening, but chunks of synrock fall away, and the air fills with acrid dust that bites at my lungs when I inhale. Should have brought a mask , I realize, but it's a bit late now, and anyway, the sound and feel of the drill is changing as the bit skitters across bright metal. "Hah!" I mutter, resisting the frantic itch that keeps prodding me to look over my shoulder.

It takes me a couple of minutes to get enough of the surface of the doorframe exposed to be sure what I'm looking at, but the more I see, the happier I am. The concrete tunnel is a hollow tube, and the door is some kind of inspection hatch near a join. If I'm right, the join isn't a T-gate, it's a physical bulkhead designed to seal segments off in event of a pressure breach, which means this is part of a larger physical structure. This door will lead into the pressure door mechanism, and maybe via an airlock into other adjacent segments—up and down as well as fore and aft, I hope. The only problem is, the door's locked.

I dig around in my pockets for one of the toys I took from the garage. Chopped-up magnesium from a block the hiking shop sold me, mixed with deliberately rusted iron filings in a candle-wax base—a crude thermite charge. I stick a gobbet of the stuff above the lock mechanism (which is annoyingly anchored in the concrete), flick my lighter under it, then jerk my hand back and turn away fast. Even with my eyelids tightly shut the flare is blindingly intense, leaving purple afterimages of the outline of my arm. There's a loud hissing sputter, and I wait for a slow count of thirty before I turn round and push hard on the door. It refuses to budge for a moment, then silently gives way. The lock is a glowing hole in the partially exposed doorframe—I hope we don't have a pressure excursion anytime soon.

I step through the door and glance around. I'm in a small room with some kind of crude-looking machine occupying most of it. Gas bottles, axles, physical valves. It looks as if it was built during the stone age and designed to be maintained using tools from the hardware store. Maybe it was? I scratch my head. If this hab was originally configured for some kind of paleo cult, made to resemble one of the polities of old Urth, it would be relatively easy for Yourdon and Fiore to tailor to their purposes, wouldn't it? Maybe that's what old-me meant about this place having unique features suiting it to their needs. There's a ladder, of all things, bolted to the wall, and a hatch in the floor. I go over to the hatch in the floor, which is secured by a handwheel. Turning the wheel isn't too hard, and after a moment there's a faint breeze as the hatch rises and rotates out of the way.

Hmm . There's a pressure imbalance, but it's nothing major. That means open doorways, maybe a whole deck down below. But I said I'd go up, didn't I? I start to climb. The hatch in the ceiling has another wheel, and it takes me longer to rotate it, but there's some sort of spring mechanism inside it that raises it out of the way. That's smart design for you. They assume that pressure breaches come from outside, which in a rotating cylinder hab like this means down, so you have to exert force to open a hatch leading down. But hatches leading up have a passive power assist to make it easy to get away from the blowout. I like that philosophy: It's going to make life ever so much easier.

I climb into the tunnel, then pause to pull my headlamp on. Getting it lit, I climb up above the hatch. Then I step sideways off the ladder and close it behind me. I'm now at the bottom of a dark tunnel occupied only by the ladder, punctuated by shadows far above me, and the trail I've left leads down instead of up. I hope there are doors up there. It would be really shitty luck to have gotten this far only to find they're all jammed or depressurized or something.