Silly man! He didn't need to assume responsibility for it, just be concerned for their safety and say he had no idea why it happened. Now he looks bad, and he could have been blameless. I imagine he was in a hurry to distance himself from the incident - they have to report all such things and be quizzed about it, as anyone injured could claim against the bus company.
I was on a bus the other day which was stopping and starting in rush hour traffic. An older lady who had stood up ready to get off at the next stop was caught unawares by one sudden start and fell back onto her behind, bumping her head on the way down. She insisted she was OK. and her sister would have helped her up and gone on their way, but the driver insisted on calling for first aid and for a relief bus to take the rest of us aboard. If he had not looked after her, he would have been in trouble.