Good point. As somewhat of a nitpick, I've heard that with some types of brain injury (especially those resulting from rotational forces and indirect impacts), a large portion of the total damage may be from secondary effects - my understanding is that this results from a chemical cascade that may only appreciably occur 4-30 hours after the event.

No citations and won't even bother for a hypothetical case - just a bit that I've read here and there. Google keywords are probably "secondary injury", "DAI", and "diffuse axonal injury".