“Thanks,” Natalya said, without looking at her. She started up the drill again, and this time its whir sounded smooth and clear; the blade dug eagerly into the ice, with an enormous crunching sound like a giant biting into an apple. Park stood beside the drill and watched as it cut a perfect circle into the ice. She tucked the metal stake into the inner pocket of her jacket, feeling it weigh down her torso. The frigid air bit into her bones through her suit, but somehow she still felt weary, rubbed raw; she could have lain flat on the rime and gone to sleep. Maybe she ought to leave the biodome more often, she thought, watching Natalya and the Earthmover burrow deeper into the ice. Maybe there were more things she could do to help the crew—things that didn’t involve letting people cry on her floor all night. Maybe if she pitched in, made more of a physical effort for the community, the collective perception of her would improve. But what was she going to do about this discovery? Maybe Keller could handle it . . .

There was the violent sound of ice cracking; the drill lurched forward like a bucking horse. Park looked nervously at the hole that it had made, but it didn’t seem to be any larger, nor were there any hairline cracks surging toward her on the ground. She turned to ask Natalya if something was wrong—but suddenly she could hear a high, piercing whistle, something that sounded like a metallic scream far behind her, made wavery by the howling wind. And also a strange sound from the cab: Natalya said something like, “Oo!” and jerked the drill free of its cavity, throwing the Earthmover into reverse. Park looked at her dumbly; had the drill gotten stuck again?

“Move!” Natalya screamed again.

Then Park saw it: the cliff above her, the white ledge of it sliding forward slowly, ponderously, almost ridiculously, like a slow-motion fist tipping forward to ready itself for a punch. Park watched it, uncomprehending. She thought, wearily, that the falling ice would cover up their hole, and they would have to start all over again.

Too late did she realize what was going on: the drill had malfunctioned again, punched too strong a hole into the ice, upsetting some deep structural foundation of the cliffs above. They were falling! And falling towards her. But by then her feet seemed rooted to the ground. She stared. Her mind was a thundering blankness. She couldn’t seem to make the connection between her own body and the enormous white waves that seemed to be moving above her. She thought, absurdly: They’re too big. There’s nowhere to run.

Then something hard collided with her body and flung her viciously out of the way.