Judging from the advertisement on the back, I think that was just a regular public transit bus and not a school bus. Though, maybe all buses should have that option for the rare times they're unloading unaccompanied kids.

A cow is not a slave, khaleesi .

Seems kind of monstrous to lock your employee in with a knife wielding psycho just to prevent him from stealing some cash. Maybe there's something I'm missing, but I agree with modulous that she doesn't seem to be protected by anything.