Bank robbery

A medium sized bank with multiple windows, 4 lines of people, and a vault in the back that can't be accessed without a power drill, or code which none of the banktellers know. The only way the User can get the code is by kidnapping a money transferrer who does know the code. If they use the power drill, or fire a shot, everyone will be alarmed. And if someone figures out the source of it, the police will be called. The police will arrive in 7 minutes, if someone does it.