Yeah, that's not promising. God knows what had happened to this kid - he's a Voidtrecker, sure, but he's also a kid - while he'd been missing. "Okay, stop." He holds one finger up about eight inches from Senku's face. "Follow the finger with your eyes. Don't move your head." He moves it from side to side, then up and down, watching the kid's face the entire time. It's a rudimentary concussion test, but a baseline is a baseline and it'll give him some idea what he's working with.

(He has no idea what he's going to do if the kid's injured. Nothing quite like trying to get medical treatment for someone accused of terrorism.)