The only time I have ever had to unholster my weapon with the intent to kill if necessary was when a local thug was beating his GF who was pregnant and threated to "Pistol whip my azz" I called 911 told them I was in the street and armed and not on his property. Told him that I was armed and if he approached me I would do what was necessary, that the police was on the way. He ran into the woods, cops found him after about 2 hours hiding at his cousin house. After telling 911 I was armed and he was beating his GF 10 cop cars showed up - 45 minutes later. When one officer started to approach me I removed the clip, opened the chamber and placed the clip and round on the ground at my feet and showed him the gun was safe - The officer told me that the perp was a known menace and has had the cops called on him several times weekly for about 3 years ranging from theft, assault to drug dealing. The officer said that they had waited longer hoping he would get shot and they would not have to deal with him again.
GF did not press charges cause they were in "love", but when he beat up his grandmother a few months later she did and had him locked up for a few months.
Chances of being in a mass shooting is very small. Chances of being able to save your own life or others is much higher in 1 on 1 or small groups, chances of Archie being wrong - 100%, chances of Archie admiting he is wrong - 0%