Those mice have vanished past the grates, with no sign they're going to come out and answer her. But as Nel rummages in her rucksack, a fresh wave of squeaks approaches from the other direction, accompanied by footsteps. The new mice swarm around her and pass, following the same path as the mice she'd followed.

"Oh, hey... Nel, right?" Russell asks as he comes close, mostly watching the disappearing mice. "You're here too? Don't tell me..."

Much as he'd like to deny it, it seems unlikely that the mice are just singling him and Walter out for... whatever's going on.