That is what I am trying to get at, Dale. Gunfights are often won or lost in fractions of a second. Innocents are killed in fractions of a second.
My point is that one must be as certain as they can possibly be - they must have the mental commitment to act - prior to an incident. That relates directly to the OODA loop.
When a bad guy posing a lethal threat is encountered they are either at "A" or waiting on "A". Given everything a human being does from brushing their teeth to participating in a lethal encounter requires OODA, being at "D" or earlier puts you behind the threat.
I have never had to end a threat confronting innocents. But I know as surely as I know my own name I could not tolerate spending the rest of my days wondering if I could have saved just one by acting instead of exiting.
"Sheepdogs". That has come up recently, at the moment I do not recall if it was in this thread or another. But I know how to identify one.
On September 11th, 2001. On airliners over PA and DC. The sheepdogs said without hesitation: "God I wish I could have been there, maybe I could have made a difference." The not a sheepdogs said, "Thank God I was not on those airplanes."