"I don't know," he whispers back.

Squeeeeak.

Whatever it is, though, it sounds like it's coming from underneath a car just ahead of them. Felix begins to drift that way, mumbling a quick, "'Scuse me," as he crosses paths with another pedestrian; once he's there, he wipes off his hands on his knees, squats down, then realizes that's not going to work and rocks forward to kneel on the curb.