I'd say 70% of the blame to the driver and 30% to the engineer. In the first place, nobody is suppose to stand at the door at all times. If the bus is full, the driver shouldn't pick up more passengers as simple as that. On the other hand, the engineer shouldn't board a bus that is so pack. Also, he might have been leaning his body against the door and he probably didn't expect the door to open so soon.