Not a teacher only a native.
The sentence certainly does sound awkward to me as a native. I would say it something like this: 'When the bus arrived, the door openend and the passengers got on from the front, while the other passangers got off from the rear of the bus.'
I believe the proper term for getting off a bus is 'alight' and 'board' is for getting on. So you could say 'When the bus arrived, the door opened and the passengers boarded from the front, while the other passengers alighted from the rear of the bus.'
Like I said I'm not a teacher but I hope this helps, please ask if you need anything clearing up.
Student or Learner