"I hate sitting still," he whines, loud enough that the police officer driving them can hear him. Better he think that they're just sitting in the back complaining and stressing about how mad their caretakers will be than possibly plan an escape.

And then, in a whisper:

"Up my sleeve. I'll stash them before we get to the jailhouse." They're small enough that he can slip them out and into the street and come find them later. That's probably the best course of action, unfortunately. "The bump key just looks like a house key."