Walter debates rolling his eyes - earned reaction or no, Russell might not even notice given how they're both preoccupied - but instead sighs and sets his shoulders.

"Whatever we do, we should start blocking off the doorways. Keep the water channeled down the hallway. And if you're heading out in the hall, so am I."

He doesn't actually want to be trapped in his room - the guilt of inaction would make a wreck of him. Even when his own (literal) worldview's taken a hit, there's still too much going on.

"If not... we'd better be quick, all the same."