> I expect a bunch of debris radiating out from the point of collision
The debris was moving at a rate before the explosion.
Think of it like blowing up a balloon in the car. The fragments continue moving in the general direction of the car. Nothing as negated that motion. One pieces hit the car floor, ceiling, sides, people, etc. do they stop their relative motion. It would be improbably that a fragment would go in the reverse direction of the car, even if to a bystander the fragment seems to me moving a bit slower than the other pack.
The debris was moving at a rate before the explosion.
Think of it like blowing up a balloon in the car. The fragments continue moving in the general direction of the car. Nothing as negated that motion. One pieces hit the car floor, ceiling, sides, people, etc. do they stop their relative motion. It would be improbably that a fragment would go in the reverse direction of the car, even if to a bystander the fragment seems to me moving a bit slower than the other pack.