I found over the years of analyzing officer involved shootings that success was heavily based on a perfect balance of Mindset, Marksmanship, and Gun Handling/Tactics. Huge failures often resulted from Mindset issues. Contrary to popular belief, violence at high levels is learned and is not normal. Folks who can talk all sorts of crap about "what I would do" often don't or can't when the time comes, or make huge mistakes because of an inability to control themselves to the societal expectations for "good guys". Bad guys have a totally different set of expectations and their levels of control are different. Think about most robbery confrontations or criminal assaults. By nature these are not difficult marksmanship problems (inside 3 yards and any hit counts). Criminal mindset is often not hindered by any civilized societal expectations. In their culture, shooting victims is a rite of passage and not an issue. They often win the Mindset battle with most they face. One huge benefit cops get over the rest of those who lead an armed lifestyle is cops learn how to administer violence fairly early through pure exposure where most of the rest of society gets no immersion in this. I know for me, coming out of a Leave it to Beaver home life growing up and a liberal college experience, I had to quickly learn through doing to roll violence at the 100% level. You find out soon that the Academy training level used on other recruits does not work on the street. Once you figure out how to run the hose at wide open, you then need to figure out how to control the hose and turn it both on and off at switch level speed. There are really no "schools" for this part of the equation in civilized society. In criminal culture...school is always in session on violence application. Your Bill Drill or FAST time does not matter at all if you missed the assault ques, and lack the awareness to trigger the lethal violence switch against a criminal who is feeling emotional and physical elation and ectasy by shanking you.