A criticism, and a thought.
Although it was idiotic actions that made this happen, I do hope that everyone involved will be o.k.
Generous of you, considering the wife wasn't handling the gun, and the guy in the next stall had nothing to do with how the weapon was handled.
Sorry for the sarcasm, but your comment read very badly. You may have meant it in a nice way, but if so, your meaning didn't come across. It seemed to imply that it's ok not to wish well on those who injure themselves through stupidity. A lot of folks here will refer to natural selection or Darwin awards, but I think most of us will still hope for the full recovery of the inept, not to mention their victims.
A thought on semi-auto weapons going full-auto:
It happened to my group, last week.
I was at a range qual for defense contractors last week, at a public range near Fort Benning, when a semi-auto AR went full auto. Shooter was having a hard time getting a good zero, so the instructor and I tried it out. Trigger seemed rough, compared to those on the two other ARs in use. I was able to achieve a zero-qualifying group, but wasn't happy with the way the trigger broke. The instructor (prior Ranger) tried it, and it fired a two-shot burst. He loaded another three round magazine, to make sure he hadn't flinched or pulled a short reset. First shot fired normally. Second trigger pull produced another two-shot burst.
We turned the weapon in to the gunsmith, to check the sear and disconnect. Suspect the issue causing full auto mode will be related to the crappy trigger pull.
Again, this was a semi-auto, short barreled AR with collapsible stock, not a selective fire M4. It could only go full auto through a malfunction.
If a fairly high grade, high dollar carbine can inadvertently go full auto, I have no trouble believing a low grade, pot metal 9mm pistol could do so. How it started firing in the first place is another question, although a slam-fire or a stuck firing pin plus impact could explain it.
Then again, so could a finger inside the trigger guard, followed by panic.
And the guy should not have put a loaded weapon down on the bench, especially with the muzzle not downrange.