But judging by the clip, the projectile didn't go supersonic, just based on the sheer power of it (Abe collapsed instantly). You could get hit a dozen times with a small energy projectile and still stay standing (for a couple of seconds at least).
I don't think so - the main reason (apart form saving weight) why we have small fast projectiles in rifles (instead of huge heavy balls like before) is hydrostatic shock. Also faster bullets penetrate armor better but that's another topic.
Projectile crossing certain speed threshold (for mostly liquid bodies we all have) will produce massive temporary cavity in the body, and shockwave from this will ripple through surrounding tissue. Imagine 7.5mm wide bullet blasting 10-15cm hole within the body, although entry point is not much bigger than bullet.
Just watch any shooting video with ballistic gels, they do tend to slow it down to see how much damage bullet is doing.
Any organ will become mushy pieces and goo. Even currently standard military 5.56mm is capable of this from close distance, if its not slowed/fractured by some big bones. And they are phasing it out for bigger and similarly fast (if not faster) cartridge for all these reasons.