[ The obvious answer has also occurred to Qubit, don't worry. ]

They seem to respond to sound, so a loud enough noise ought to get their attention. [ Normally he could just gut a cash register or two and slap together whatever they need, but if he's not careful he could put himself out of commission at the worst possible moment. So he shrugs. ] If we can't find anything suitable, I could always run up and yell at them.