Upgrade(89)

I turned and ran, leaping down to the next landing and continuing my sprinting descent until I reached the door for 26.

Locked.

I dug another door breach out of my bag, slapped the charge on near the handle, set the timer for twenty seconds, and ran down to 24.

After the chest-squeezing explosion, I returned to 26. The door had been blown fifteen feet into the next floor. I stepped through the wreckage, my eyes watering against the heavy C-4 stench of tar and motor oil.

I could see without the flashlight here. The floor was mostly cubicle space, with a few offices and conference rooms along the exterior walls. I hustled to the northeast stairwell, opened the door. The flashlight shone through a thick layer of smoke, and there was another scent in the air: the sickly-sweet odor of charred flesh.

Four floors above me, I saw the glimmer of more concertina wire.

I sprinted down a row of cubicles.

There was no smoke in the southeast stairwell, but I heard voices far below and saw more wire blocking the stairwell several floors above.

As I ran for the last stairwell, I marveled at Kara’s planning. She’d built a lethal barricade between any threat and herself. But to get out of the building, she’d have to make her way down these stairwells, fighting through attackers along the way. And no doubt the DoD—or whoever they had hunting us—would have reinforcements guarding the exits too. SWAT snipers on overwatch, at the very least.

Even if all went well for me, I’d be facing the same problem.

I was betting Kara had an escape route up her sleeve. An elevator shaft? Some secret stairwell that wasn’t in the blueprints? If she didn’t—or if I couldn’t figure it out in time—this would be a suicide mission.

Two minutes—if Edwin had told me the truth—before JTF-Black’s arrival.

I stepped into the southwest stairwell.

No smoke. No noise. No wire immediately above.

I surged up the stairs, powering my way through 28.

29.





30.


Gunshots erupted somewhere in the building—the racket of automatic fire, and then another blast, not above or below, but lateral to my position.

I kept climbing.

Through 31.





32.


Just two floors away, and I was searching meticulously, but I didn’t see a threat—no sign of wire or explosives.

Light bled through around the seams of the door to 34. Was it rigged to blow? I pressed my face to the edges of the door and inhaled—no trace of that motor oil smell.

JTF-Black would be landing in one minute.

I grabbed the door handle, tried to turn it.

Locked. And a breach charge would reveal my presence.

But these were fire stairs. Doors could be locked from the outside, but from the inside, they had to be easily opened in case of an emergency. Usually, this was accomplished by means of an REX (request-to-exit) sensor on the door’s interior side, which uses passive infrared to detect temperature changes in proximity to the door. If the sensor detects a change in temperature—caused by a person approaching—it transmits a message to unlock the door.

The keyword there being change in temperature. Not necessarily an increase.

I rummaged through my pack, found the can of compressed air. I ripped off the packaging, inserted the straw into the nozzle, and got down on the floor, hoping there would be enough space between the bottom of the door and the threshold plate to slide the straw underneath.

I found a chip in the threshold, worked the straw through, and held the can upside down. If I sprayed it upright, only the fluorocarbon vapor at the top would be released. But when inverted, a liquid is forced out instead. This liquid, under great pressure, quickly evaporates and expands to become a gas at room temperature.

The thermodynamic process of adiabatic cooling would hopefully chill the immediate area on the other side of the door and—if I was right about all this—trick the sensor into thinking someone was approaching from the other side.

I squeezed the trigger, listening as the liquid hissed out on the other side, the can growing cold in my hand.

I took off my NightShades, reached up, grabbed the door handle.

This time it turned.

It occurred to me that there might also be a secondary sensor on the door itself, which, if opened, would break the alignment with its partner sensor on a facing wall and trigger an alarm—something as simple as a phone message to Kara and her security team.

Nothing I could do about that. I was out of time.

As I eased the door open, I heard machine-gun fire high above, followed by the deeper, locomotive chugging of a chain gun.

And then a shuddering boom.

I charged into the light, my Five-seveN up, fluorescents burning down on a white corridor, something pulling at my attention from the left—

I turned just in time to see a burning Black Hawk falling past a wall of windows, the rotors still spinning, cutting through the building in a cataclysm of exploding glass and cloven metal, the pilots screaming in the cockpit—and gone.

Then 3.8 seconds later, an explosion rocked the building as the helicopter smashed into Cedar Street.

And I was on the move, jogging down the corridor past rooms filled with cots and medical equipment, wondering if this was where Kara’s viral test group had been given her experimental upgrade for the first time.

On the other side of the elevators, I saw a stainless steel bioreactor.