This is John Correia (ASP) post on the incident. Lots of good points. Very important to carry with a round in the chamber as even experts will forget to chamber in an encounter. Lots of videos of defenders dying because their gun wasn't chambered. No hits on the bad guy from 5 yards to 50 yards so practice under extreme stress - an audience watching you shoot solo, action competitions, and shooting under physical exertion (run, do pushups, etc before shooting). Practice your support hand shooting along with support hand only reloads and malfunction clearing. Lastly, consider your decision whether to get involved or not beforehand as you don't have time in an actual situation to figure things out.
Holy hell, I just got current on the Twin Falls, Idaho In n Out active shooting and there are several details that only came out in the last day or 2 that have been utterly and completely missed by the defensive training community.
The hero who didn't want to draw his gun, Austin Scott James, is a legit hero who should be applauded. He also, after being shot in the right shoulder and severing his brachial artery, drew his gun with his support hand and tried to engage the killer with it, but couldn't because he was carrying it with the chamber empty.
An unnamed woman in the fog of war was confronted by the gunman, ducked behind his car, and picked up the gunman's discarded pistol. The gunman had discarded the pistol because it malfunctioned, and she couldn't fix it. So she ran and tossed it.
The off duty Idaho State Patrolman is a hero who coordinated getting employees out of harm's way and is a hero. He also had a confrontation with the gunman at about 5-6 yards and did not get hits on that gunman, who then went on to shoot a Good Samaritan right next to the trooper and also kill two more people.
I can say that I have some inside information from a reliable source that I cannot name at their request that the only wound the gunman suffered was the self-inflicted gunshot wound. So Mr. Salinas, an absolute hero and another who should be lionized, did not get any hits on him.
Additional lessons that have thus far been ignored:
1. Carry your gun chamber full. Never assume you will have a second hand available to chamber your firearm, and all the goofy workarounds to chamber a gun support hand only are probably not useful while fighting off the blinding pain of being shot in the shoulder. Carry your gun chamber full.
2. You don't need to be a firearms expert, but learning the basic operation of a semi-automatic firearm and knowing how to clear any kind of malfunction in it is a good skill to have. Battlefield pickups are exceedingly rare in real gunfights (this is only the third one I have ever seen actually caught on camera in over 50,000 incidents on video analyzed) but knowing how to clear a malfunction is important. Carrying your own gun is better, of course, so that you don't have to rely on an unknown gun of unknown provenance with unknown ammunition that has shown that it is not reliable already.
3. Marksmanship matters. It's exceedingly difficult to miss fast enough to win a gunfight, but very easy to hit slow enough to lose one. The trooper missed from 5ish yards, and Mr. Salinas from significantly farther. Maybe 40-50 yards. That last one is a long shot for sure, so start with the shorter distances of 3-7 and once you're really good there work outward. Misses don't deter committed killers for long.