Fighting to my feet, I slung the bag onto the gurney. The corridor still empty. The rear sliding doors just behind us.

With both hands I slammed into the gurney, getting it moving toward the rear exit. It was too slow, and I was too weak. It clipped a doorway, and one of the giant oxygen tanks bounced off, clanging on the floor, the loudest sound I’d ever heard.

Patrick and I halted. Our eyes met.

A moment of breath-held silence.

Then we heard the shuffling of dozens of feet. A moment later a wall of Hosts swept around the corner at the end of the hall. They’d reversed course from the blocked front stairwell, tracking the sound.

Patrick rushed back and pried open the doors to the rear alley. They parted. I propelled the gurney toward the opening, risking a look behind me.

They were almost on me. It was too late.

Patrick reached past my face, grabbed a fistful of my shirt at the rear collar, and hurled me up onto the stacked tanks. My momentum started the wheels turning. I rode the gurney out through the rear doors.

Inches from my face, the end of his tube popped off the H tank. I reached for it, but it flew away like a fly fishing line as I rolled clear of the building on the gurney.

Twisting, I stared back at Patrick in time to see the shotgun rise.

But he wasn’t aiming at the Hosts.

He was aiming at the floor.

I realized what he was doing an instant before it happened.

The shotgun roared, the shot striking the end of the oxygen tank. It rocketed forward, lifting off the floor and impaling the lead Host right through the stomach. The tank bore a massive dent but somehow it hadn’t exploded.

That was about to change.

Patrick shuck-shucked the shotgun and fired again. The tank exploded, wiping out the Chaser it was embedded in and the wall of Hosts behind it. The fireball filled the corridor. Patrick hopped back through the doors into the alley as flame blossomed out into the cold night. Heat billowed over us and then flowed up and away.

I slid off the gurney, groping on the cold ground, finally coming up with the tube. My hands chased it to the end. Patrick waited for me, his breath still held.

I shoved the tube back over the hissing nozzle. Patrick pulled his mask away from his face until the oxygen shot up the line, fluttering his hair. Then he snapped the mask into place, blew a big exhalation through the one-way valve, and started breathing again.

I started breathing, too.

We didn’t pause to celebrate.

He took one side of the gurney, and I took the other. Side by side we hurried up the alley, wheels rattling like crazy over the bumpy asphalt.

As we neared the edge of the alley, Patrick said, “Slow up, slow up.”