At least the tire and oil filter are ok? To be honest, I see that happen on a lot of fire trucks and material handling equipment.
My theory is there was a crack or lack of lubrication somewhere that as the torque of the engine went up, it took the path of least resistance and caused the crack to completely snap, or the heat caused a break in the cast iron. At that point, if the wheel starts swinging around everywhere, it will take everything else with it nearby. Actually happened to my fire truck recently. =(