Kennedy’s rearward action happened after the initial two inch impact push. Since the initial two inch forward movement happened on impact, that cancels out any overt action afterwards.
Some people who have shot human skulls filled with ballistic gelatin claim that a “jet effect” will bounce the target toward the shooter. I can’t say for sure since Jackie and the governor act away from the wound debris.
It could also been reflex response to a 162 grain bullet traveling through someone’s brain.
Thanks... Interesting.