I can't ever remember seeing an actual video of a civilian shooting using pistols where at least one person didn't seem to empty their gun or come close to it.
I haven't seen a ton of videos though, just a few.
It always seems one person, usually the one who walks away, just rapidly unloads their gun on the other person.
I also can't really remember seeing a shooting where anyone fired 15-20 times.
There was the California ?drugstore owner? who went and got another gun to shoot someone.
Looking at surveillance cameras of such things seems the best way to tell in my mind.
I carry 11+1 and feel pretty comfortable with that.