With a look first to Manning, then to me, Instancer springs from the platform, lightly and powerfully, onto the uptown express track to the rear of the stopped train.

He flees in the downtown direction into the dark.

Manning leaps after him, reloading.

Two pairs of uniformed officers (the backup teams Manning had called for) sprint now onto the platform from adjacent stairwells. They vault after Manning into the pursuit.

Something makes me turn and glance to the platform above me. Rachel stands at the brink, her hair spiky wild, the whites of her eyes livid and bloodshot.

RACHEL

Go after him! What are you waiting for?

I take off. Instancer is already fifty yards down the track. Flashing alarm lights obscure him. I’m struggling to keep my footing on the wet, greasy railroad ties. I hear one of the uniforms shout that the fugitive has bolted through a door or hatch into a lateral shaftway.

I’m sixty feet behind Manning and forty back of the first patrol officers. I see Manning, then the officers, duck right and into the lateral doorway.

I follow.

The passageway leads to a steam tunnel. You drop through a circular hatch and down a ladder well.

What the fuck?

This second tunnel runs parallel to the subway line but one level below. A single narrow-gauge track runs down its midline, apparently for maintenance handcars. The tunnel is an intestine of insulated high-pressure steam pipes, mounted along walls glistening with oily, gunk-dripping stormwater. Red and yellow emergency lights flash. Alarms sound. Jetting steam obscures everything.

I hear a gunshot and race after it.

Fifty yards.

A hundred.

Suddenly the tunnel opens onto a vaulted, tile-walled cavern. Floodwater thunders like Niagara from a dozen breaches in the overhead. A catwalk crosses the atrium. Storm runoff sluices in unimaginable volumes across the void. Roiling, viscous fluid fills the belly of the vault, thirty feet below.

Instancer flees across the catwalk.

Manning chases him.

The patrol officers pursue along a second walkway, farther uptown.

Suddenly Instancer trips. He slips and plunges down a four-step descender, but catches himself, nimble as a cat, and hauls himself back up.

He races into another hatchway.

A continuation of the steam tunnel.

I crab-scoot across the catwalk, clinging to the rails in a death grip.

Into the second steam tunnel.

A hundred feet ahead, Manning overhauls Instancer.

The pair grapple.

I’m slogging as fast as I can, straining to see. Steam jets everywhere from the wall-mounted pipes.

I see Manning seize Instancer in some kind of wrestler’s hold. For an instant it looks as if Manning gains the upper hand. Then Instancer punches with his elbow into one of the steam pipes.

The vessel punctures.

Scalding steam blasts into Manning and Instancer, obscuring them both.

I glimpse Manning among the steam as he reels, shielding his face.

He lets go of Instancer.

Instancer, lit scarlet by the flashing emergency lights, stands stock-still amid the searing steam.