I have a lot less confidence in my ability to use firearms under pressure than I used to.
This is a very helpful story, thank you for posting it.
In my opinion, everyone who carries a gun should train with it. Most gun owners, in my experience, train for safety and marksmanship and then stop. This is acceptable for someone who wants to enjoy certain shooting sports but doesn't have any intention to be able to use a gun defensively.
Next is training for gunfighting. This encompasses a number of different skills, including using cover, shooting on the move, reloading, ammunition management, shoot/no shoot training, the law, and so on. The bulk of people I've met who carry a gun (professionally or simply for their own protection) obtain some level of training in this area and then stop.
On the higher end of gunfighting skills is force-on-force training with stress inoculation. You'll know if the stress inoculation is good if you find yourself experiencing tunnel vision, auditory exclusion, time dilation, and tachycardia. If you take some training that includes force-on-force training (preferably with Simunitions) you will probably find that your ability to use firearms under pressure will be significantly improved.
I consider myself a lifelong student of shooting and I think it behooves anyone who carries a gun to do the same. I am certified as a Range Safety Officer, Pistol Coach and Basic Pistol Instructor. I focus my instructional efforts on bringing new shooters into the sport safely and making shooting fun for my students. While I've taken some advanced classes I've never been any sort of armed professional and I am not qualified to teach advanced classes.