This isn't the movies. If I feel he is attempting to shift and aim, he will be swiss cheese. This is why, if he had the drop on me, I said that I would indeed have to play Russian roulette because, unless he makes it clear that he does indeed plan bodily harm (and therefore warrants risking everything to attempt to turn the tables) , going for a weapon would be an invitation to get shot.
Bullets do not kill you instantly - no, but if they are larger than a..22, they can and will throw your ass to the ground. (12-gauge shotty will do this nicely too) There's a lot of kinetic energy there. Like taking a full - on punch from a large individual.
Let's put it this way. I've seen a fellow US Marine take a. 223 round to the foot at the rifle range. (someone was a really bad shot, hit the wooden support of the target, which, freakishly managed to find a knot in the wood, which caused the round to angle down into the target pulling pit after penetrating the post.)
He was instantly SCREAMING. That little less than quarter inch in diameter piece of metal flew 500 yards, penetrating half an inch of wood and then punctured a combat boot causing tremendous pain.
At close range it would probably be like getting hit with a baseball bat.