The story is short and simple.

Passenger in car takes out his gun to show off to the driver and winds up shooting himself in the leg. How did it happen? The gun “went off”.

Folks, guns do not just “go off”. That’d be like matches suddenly igniting and starting a fire. Or a car suddenly starting and driving itself somewhere. Or a lawn mower spontaneously starting up and cutting the grass. Or a book reading itself. For any of these actions to happen, it requires someone to make them happen. Someone must strike the match, someone must start the car or the mower, someone must read the book. And as such, someone must fire the gun.

When things like this happen, it’s usually due to negligence. They put their finger on the trigger and fired it. Sure it was unintentional, but it was also negligent.

Follow the rules.

If you follow the rules, things like this shouldn’t happen. I won’t say they won’t happen because we’re human and we make mistakes. But that’s one of the things about the rules (whichever ruleset you follow). They are layered. If one rule is violated, ugly things can be averted. It takes a violation of more than 1 rule for bad things to happen. If you do your best to always follow all the rules, you should be in good shape. Unfortunately in this case, the first 3 of Cooper’s rules were violated, and at least the first 2 of the NRA rules were violated.