A lot of guessing and assuming there, champ. How many times have you been involved in life-or-death CQC scenarios? Got any commando training techniques you'd like to share with us, that you are basing your assumptions on?
And, by the way, point blank isn't execution style... it's exactly the distance at which an attacker with blunt weapons or knifes would be shot at.
Do you have anything to say that somehow a person in the middle of a jostling shifting mob can maintain a steady enough aim to hit somebody in the head?