I didn't notice a lot of damage to the bus itself so I'm assuming this was done by one individual boarding and standing at the front then emptying a forty round clip from a AK-47. The rounds would have easily penetrated multiple bodies. Also, whoever did this left immediately after without checking for survivors which leads me to believe that they were sending a message more than trying to kill them all. Then again, what the hell do I know?
40 round AK magazines are only found in a parallel universe.
