“I know what a wall is, asshole. Why is there a wall in a hallway?”

He swept his flashlight left and right, revealing the walls of the hallway we’d been following, which terminated abruptly into the solid mass of the wall ahead. I pushed past him to touch the wall. It was surprisingly solid, but rang hollowly when I knocked on it.

“Maybe there’s an opening further down,” I said, and backed up down the hallway until I found another branch. I stood aside for Benny to take the lead, and we followed the passage until a door opened up to our left.

Inside, we found that the room had been sealed off as well, a doorway visible on the opposite wall, but filled up with a sheet of some kind of craggy metal or plastic. “Interesting,” I said.

Benny led me further down the hallway, into a particularly large room, flooring uneven with rubble, that appeared to be some sort of lecture hall or schmooze space rather than a functional lab. Across the back of this room, too, someone had built a wall.

I laid my palm over the ancient wall, which carved through rooms and hallways so adamantly. It was distinctive by being no one particular thing; the wall looked as if it had been put together out of pieces of whatever else was in the room, rather than being an intentional part of the décor. It had been assembled very solidly, too, or else the monsters on this ship had avoided it the same way they’d avoided some of the labs elsewhere on the ship. When I knocked on the craggy, uneven surface, it tolled hollowly.

The pounding in my head resounded in unison with the echoes from the solid wall. I reached up to rub the base of my skull, then thought the better of it.

“I bet Lab 17 is inside,” I said. “Someone built this wall. Maybe Mara Zhu, to keep the other scientists inside. Or maybe the scientists built it, so that none of those monsters could get through.” I stepped back from the wall and sighed. “Bad news for us, good news for the Ministers. They’ll be able to cut right through.”

“Maybe not.” Benny’s voice was muffled; he’d pulled his shirt up over his mouth and nose and was bracing his flashlight between cheek and shoulder. He’d managed to pry open one of the rotten old panels on the wall, and was shining the light inside. “Take a look at this.”

I peered in over his shoulder and saw a mesh of wires and solid lumps of something unidentifiable, like swollen mushrooms, wedged between the oddly sized pieces of wall. “What am I looking at?”

Benny pointed at the wires without touching them. “These are live. I bet they’re wired right into the ship. There’s a lot of voltage going through them, too—if you put your hand close you’ll feel it. Don’t touch.”

I reached out carefully, my hand beside his. The skin on my arm prickled.