The bullet "appears" slow down in the milliseconds immediately prior to impact and then "SCREAMS" through the deer between seconds 5 and 6 disappearing completely on the far side with little to no atmospheric interference seen to indicate its post-hit flight. Probably due to subsonic conditions on the far side.
It takes the deer almost 8 SECONDS to register the hit, hunch up, and get his feet moving away from the point of impact. That is one FAST bullet and one slow reaction time for the deer.
For the deer, it was ALL OVER before the bullet's impact.