"It's open, Ken. We can walk right in." She touched his forearm, tried to bring it down but his whole body was gripped in a sudden furious tetanus. "We don't have to—"

"I told you before," he growled. "More sensible to go around." His gun arm swung to three o'clock, pointing straight at the vestibule wall. His useless eye stared straight ahead.

"Ken—" She turned, half-expecting the monsters at their backs to crash through the panes and rip his arm off. But the dogs stayed where they were, seemingly content to let the drama play out without further intervention.

"He wants us to go forward," Lubin said. "Always sets it up, always takes the initiative. All we ever do is fucking— react..."

"And blowing out a wall when the door's standing open? That's not a reaction?"

Lubin shook his head. "It's an escape route."

He fired. The shipworm plunged into the side wall, spinning fast enough to shatter an event horizon. The wall erupted like a tabletop Vesuvius; filthy grey cumulus billowed out and engulfed them in an instant. Stinging particles sandblasted Clarke's face. She closed her eyes, choked on the sudden sandstorm. From somewhere deep in the maelstrom, she heard the tinkle of shattering glass.

Something grabbed her wrist and yanked sideways. She opened her eyes onto the swirling, soupy aftermath of the blast. Lubin drew her towards the ruptured wall; his ravaged face loomed close. "This way. Get us in."

She steered. He lurched at her side. The air was filled with the hiss of fine sifting debris, the building sighed at its own desecration. An empty, twisted door frame leaned crazily out of the murk. Pebbles of crumbled safety glass crunched beneath their feet like a diamond snowfall.

There was no sign of the dogs, not that she'd be able to see them anyway unless they were on her. Maybe the explosion had scared them back. Maybe they'd been trained to stay outside no matter what. Or maybe, any second now, they'd find this broken doorway and pour through to finish the job...

A ragged hole resolved in the wall before them. Water ran from somewhere beyond. A ridge of torn concrete and rebar rose maybe five centimeters from the floor, the lip of a precipice; on the other side there was no floor, just a ruptured shaft a meter across, extending into darkness both above and below. Twisted veins of metal and plastic hung from precarious holdfasts, or lay wedged across the shaft at unforeseen angles. A stream of water plummeted through empty space, spilling from some ruptured pipe above, splattering against some unseen grate below.

The wall across the gap had been breached. There was darkness beyond.

"Watch this step," she said.

They emerged into a dark, high-ceilinged space that Clarke half-remembered as the main reception area. Lubin turned and aimed back at the hole through which they'd come. Nothing jumped out at them. Nothing followed.