Threat focus isn't unusual among folks placed under the stress of being attacked by someone using a weapon.
It's sometimes amazing the amount of detail someone can see regarding the weapon, even if they aren't able to recognize or understand the details of what they're seeing.
When we went through a period of using some of the large color photo threat targets it caught many of our folks by surprise when they saw their hits often clustered around the firearm being held by the threat target's 'attacker'.
Interestingly enough, this was just as prevalent and noticeable when the image of the attacker was holding a handgun down at their side, or waist level (but still pointed toward the people). They saw it, they looked at it while shooting ... and a surprising number of them clustered many of their shots around it, wherever it might have been held in relation to the attacker's body.
Naturally, when the guns were held more in line with COM, the hits were more clustered in the COM.
One time when I was doing some Sim training I was with a partner, and he took some nasty hits (lacerations) along both unprotected forearms. He was wearing a T-shirt and used a 2-handed shooting technique.
I can think of a shooting where a cop making entry during service of a search warrant was caught and jammed up in the entryway, and was the only person on the entry team able to get off a shot, fired from the hip with a pistol, when he saw an armed suspect grab a gun and point it at them. It struck the armed suspect's forearm of the 'gun arm', causing him to drop the gun. The cop remembered seeing the suspect's gun in great detail as he was trying to bring his own gun to bear and shoot at the suspect. Makes you wonder about the 'coincidence' of the shot placement.
Of course, I can think of other shootings where the suspects took hits all over their body, too.
I remember talking with a cop from another agency about an off-duty shooting where one of their cops drew against an armed suspect attempting to rob him, and as I recall the cop ended up drawing and putting 8 rounds from a Colt .45 into the suspect, essentially in a vertical string which started in the lower legs and ended up high in torso. (This incident reportedly took place at little more than arm's reach, and very rapidly, from what I was told.)