Bus driver should have parked the bus, removed the key (presuming there is one), walked away from the bus with his cell phone caling his supervisor and then the cops.
I suspect had he announced he is not going anywhee until she leaves the bus, and that the cops are on thier way, that the woman would have left of her own accord, or that some passenger who was impatient to get to their destination would have removed the woman from the bus.
The bitch desearved a beat down, but unfortunately, in this world, it was not his place to do so.