He sucked in a breath and expelled it, and punched in the code.

The lock disengaged.

He shoved the door open six inches.

He stuck the gun through and fired—one, two, three, four—and heard the chimps go silent.

He put his shoulder to the door and heaved it all the way open, already sprinting, leaning forward, hurtling down the channel, because all that mattered now was—

Pierce stopped with a convulsion that hit his body like a seizure.

One foot slipped, almost went out from under him, then caught and held on the concrete.

He was standing right at the end of the entry passage, where it opened to the room.

The momentarily silent room.

Somewhere behind him, the door fell shut and latched with a click.

Three hundred feet away, in the tunnel beyond that room, Sam and Dani heard the man scream. From far behind them, even over the noise of their running footsteps, the sound of it came through: high-pitched and saturated with fear.

They had heard the four gunshots a second or two before—had heard the chimps go silent at that instant. Then had come a weird, quiet little moment. And now Pierce was screaming like a terrified child.

Then the shrieks of the chimpanzees started up again, drowning the man out, and on the heels of that sound the gun started firing once more, fast and sporadic, over and over. All of these sounds grew fainter by the second, as the tunnel fell away behind the two of them.

Sam glanced at Dani and saw new tears in her eyes. She blinked and wiped at them, not slowing down.

“We had to,” Sam said. “We had to let them out. He would’ve got us if you hadn’t thought of that.”

If the words made her feel better, she didn’t show it.

Sam faced forward again and watched the tunnel.

They reached the end of it thirty seconds later. Like the other tunnel, it opened up into a square space at the end, though this one was far smaller—about the size of an average bedroom. It had just a single door centered on the far wall, with a keypad lock.

The only other feature at the end of the tunnel was a set of metal shelves, snugged into the right-hand corner of the end wall. It was a single upright unit, just like the dozen or more that had filled the storage room. Someone had stood this one out here by itself and left the same kind of random clutter on it: tools and boxes and cans, in no obvious order.

Dani went to the door and put her hand to the keypad. She punched in the code that started with two zeroes.

Nothing happened.

She traded a look with Sam, then pressed the seven key five times.

Nothing.

The two of them turned in place and stared back down the tunnel. They held still and listened.