I just realized the knife Vance cut that kid w wasn't his, it was the kids. When he throws the other kid, the one he basically killed pulls out a knife, and then right before Vance carves the numbers into his arm (7741 I think?) we see him take the knife from the kid. Everyone is question how he got kidnapped when 1. He can fight- like- super well and 2. He carries around a pocket knife. But he doesn't. He cut a kid with his own knife, and besides- the cops would've taken it, even if it was his, so he if it was his he wouldn't have it. Kid probably never got it back, because as I said, the cops probably took it. And even if he had kept it, Albert (The Grabber), drugs his victims, and the balloons make it harder to see and move around for the victim, so even if he had it, he would've still gotten kidnapped.