"They manage to keep the water down here radiation-free somehow." He frowned, gaze drifting away to focus on a point somewhere beyond the wall. "And that shit that poured on our heads was not."

Something to put aside for another time: were there filtration systems for the Vault that could clean radioactive water? Or was it just recycling the already-clean water they put down their drains?

"Anyway," he said, shrugging the question away. Maybe he'd try cheating at a hand of cards to get the answers out of Nick. "Let's not get hung up on perfection, Princess, because if you want that you're going to have to make everyone in here agree perfectly about our goals."

The corner of his mouth ticked up, not quite in a smile. "That's harder than changing the world."