One of stations (I've een switchng back and forth) mentioned that the first officers on the scene had to get to the bus slowly because they had no way of knowing if the sniper might be inside. The reporter said they set up a perimeter outside the bus before the attempted to approach it. Bad as that might be for the victim, I can understand the necessity of doing that.
OTOH, the victim arriving at 6:40 was an opportune time. Shifts in hospitals usually change between 6:30-7:30, so they probably had plenty of help on hand. In an emergency, all staff usually pitch in, regardless of whether you're officially scheduled to be there yet or not.
Fox saying it was the driver.