My air was almost gone. I’d lost some panicking, and my muscles burned through the rest as I shot myself through the airlock. An urge to breathe was taking hold of me, a tingling thrum running through my body as cells clamored for air. My lungs were empty. I couldn’t swim again the distance I’d come, either forward or back.

Ahead of me, down the mirror-tunnel toward the other hatch, the other junction room, a glowing orange light burned, slowly brightening. The reflected light from another orange glowstick.

I watched myself swim into the room, holding it.

Amidst all the panicked horror and desperation, I hadn’t noticed the wrongness creep up on me, but now I realized that sick feeling had been there all along, getting stronger, flavoring my more pressing concerns. This wasn’t one of the things, I realized. It was me. My double, from the other side.

We were passing each other, as planned. But the plan had failed.

We started at each other and both realized I wasn’t going to make it.

Blood diffused from my nose in billowing red clouds; the cut on my leg burned a deep, dangerous ache. My torn fingernails stung where I’d clawed at the door. I was damaged, flawed. The worse-off copy. Looking at him, unharmed, whole, I accepted that I was about to die. It was surprisingly easy.

He tilted his head, studying me. As if considering something. Or trying to see me, really see me, like I’d tried so many times to see Niko.

Do it, I thought, I’m too broken to make it. Go back. Or go forward. Just go. Live. Be the one who lives.

His expression changed. Just a little.

And then he launched himself at me. At once the sense of wrongness spiked, as if approaching some exponential maxima. His face winced at this in exact sympathy with mine, but he didn’t pull up, slow down. Instead he crashed right into me, hard. Tumbling, he wrapped his arms around me, held me, did the last thing I’d have ever expected.

He pushed his mouth to mine, and flooded my lungs with his air.

The wrongness had reached an unbearable threshold. But as his lips touched mine the sensation exploded outward, like magnets pushed against repelling poles till they slip from your fingers, flip around, snap into place. The water quivered around us; the room groaned, launching wet clouds of mud from splintering lintels, sending subsonic shockwaves shuddering through us. His breath flowed into me. I couldn’t think, let alone protest or react. Boots tumbled around us, long laces waving like antennae. I remember that.

And then he was empty, and I was full.

He pulled back, blinked, smiled a smile I knew from the mirror. It meant Oh, well, what you gonna do.

He’d picked me.

A huge rumbling crack broke over the growing crescendo of rumbles and groans, and we both looked up. The ceiling had split in a long ugly scar. But the room wasn’t collapsing on us. The split filled in almost immediately with new plaster, just as another differently-angled split bisected it, which also instantly filled.

The room was getting bigger.

My double grabbed my elbow, pushed me toward the hall he’d come in through, the way to the hatch to the other world, my world. And I started to swim. I shouldn’t have. I should have thanked him. I should have given back half his air, or dragged him after me, found some way to save him. I should have died. But I didn’t. I swam. I swam with everything I had left.

He’d made a mistake. Bet on the wrong horse. But I wouldn’t forget it. I wouldn’t forget him.

All around me the architecture was groaning, flexing, like something waking up. Plaster dust pillowed into the flooded hall in thick weightless clouds as the walls split and reformed, split and reformed, like bones breaking and healing and rebreaking, growing fractionally longer each time. I swam past a crack that didn’t fill in but puckered into a new doorway, a flap of wallpaper lengthening and hardening into door. New doorways were spawning all around me; new pits gaped open in the floor. I ignored it all. I swam. I swam for my fucking life.

The guide rope, taut as a bowstring, snapped, whipping past my face as its two endpoints pulled away from each other. It didn’t matter. I knew the way.

I swam into the easter-tile bathroom, shiny new sinks sprouting on the floor, on the ceiling; the toilet multiplying and splitting in porcelain osmosis, someone’s pretentious art project. I swam up to the ceiling—already much higher than a bathroom ceiling should be—put my hands on the wheel of the hatch, and turned.

It didn’t budge.

The groaning rumbles of hell surrounded me, my body was once again starting to tingle as my second lungful of air reached its end, my face throbbed horribly and my leg was on fire, and the wheel wouldn’t turn.

I pounded on the hatch, screaming in fury, the sound utterly lost in the cacophonous eruption of architecture beneath me.

I braced myself, gripped the wheel so hard I thought my knuckles would pop, pulled on it with everything I had.

Then I tried turning it the other direction, and the wheel spun.

I yanked it around, then forced myself up against the hatch, lungs burning, kicking hard, and pushed and swung it up and open, and then I was through, breaking through the surface. I breathed, huge and deep.

Then I coughed. Clutching the sides of the hatch, I coughed, blinked, tried to take stock of this new hexagonal room. A huge crack had opened in the floor, and all the water had drained out. The groaning and clanging was sharper up here, out of the water, but mostly coming from beneath.

I pulled myself out of the raised pillar and tumbled to the bucking ground, wiped blood from my face. I was gasping, coughing, bleeding, hurting, panicking, and also, somehow, living. Deservedly or not.

Piled to one side of the hatchway were a pair of shoes and a dry, folded t-shirt.

An ear-splitting crack rang off the walls. Bricks fell from the ceiling in a deadly shower, landing a dozen feet away. I grabbed the shirt and pulled it on over my wet torso, slipped the shoes over numb and wrinkled feet. The ground heaved beneath me like the back of a whale taking a colossal breath before diving deep, and as it did it swallowed up the bricks, incorporated them neatly into itself like a child’s plastic puzzle pieces falling into matching slots.

The floor of the bathroom, through the open hatch, was gone. Tile walls descended, vanishing into darkness. They were splitting and rejoining, like some fractal screensaver, an optical illusion in constant motion from the corner of your eye but damnably still if you looked right at it.

Something was broken. Something had diverged too far. There were too many possibilities and they couldn’t all fit. They needed more room.

Time, I decided, to get the hell out.

With a great belching snap, the floor punctured upwards and a spout of cloudy water billowed up. Another spout exploded from the other side of the room. I picked one of the circular tunnels and started running down it, as fast as I could on my hobbled leg, while behind me the depths of Downstairs sloughed and squirmed into new permutations, unseen. I was too busy living to look back.