thanks for the explanation.It has been determined that it is not feasible to "shoot to wound", as in the old cowboy shoot-im-in-the-shoulder trick, in almost any circumstances. It is virtually a universal principle in US law enforcement, and US jurisprudence, that shooting is always lethal force and that shooting to wound is both legally indefensible and tactically unsound. Shooting is reserved for lethal force situations, and the standard in the US is "shoot to stop the threat" which typically means shooting at the center chest.
Before someone brings it up, it is also standard proceedure to shoot and keep on shooting until the threat is obviously ended or the target is clearly disabled. The one-shot "stop" is more myth than reality, unless you get lucky.
Close quarters situations actually make marksmanship MORE difficult, not less.... the angles change quickly, everything happens very fast, and you have to consider that you or your weapon could be grabbed by the perp.
Most departments SOP is that if a knife-armed suspect is within 25' of police and moving forward with apparent aggression, he is to be shot.