Irrelevant and immaterial. If he intended to use his firearm for self defense he should have been competent enough with it to make it ready under stress without having an ND. I would not have accepted that from one of my soldiers or from one of the police officers I worked with after I retired from the Army. Had his ND went through his door and a window in a house across the street and hit an innocent bystander he would be in serious trouble, so no I'm not about to cut him any slack because he lived in California. California storage laws and stress are not an excuse for an ND.
Once again you have to think of where those rounds through the door are likely to end up. The guy lived in a subdivision with houses all around him. Can you predict the trajectory of a bullet after it's fired through a barrier?
Getting things as close to 100% right is one of the reasons this forum exists, it's why we have these discussions and it's why we train. We aren't going to get the number of people who get close to 100% right to be the norm if we excuse getting things wrong.
Jeff, you might not accept that from your soldiers, but I would not hold them in that high esteem. When our compound was rocketed and fired upon with enough machine gun fire in 1966 to get Gen. Westmorland to look things over, I learned a few months later when I arrived there that men, soldiers probably of all ranks were running down the second floor hallway firing indiscriminately through the screened in windows and shot most of the radiators out of our jeeps parked there.
I was given a mortar mission to fire and with about 7 rounds up in the air we suddenly realized that they were going towards a populated area. They went through the roof of a civilian house and cratered their yard pretty good. Everyone looked to me since I set the sights but it turns out the officer did a 180° math error.
I have no idea how many ad/nds were fired in the two years I was there, but there were many.
I got smacked in the back of the head by a chunk of concrete while in the mortar pits one night one someone in an interior bunker with an old BAR couldn't keep the rounds he was firing over the concrete wall.
There were two incidents of guns being pointed at ncos or officers by enlisted men while I was there.
One guy on guard one night was playing with the switch for the claymore mine. Sure enough, I was on another bucker quartering away from him when I hear a kaboom and see a cloud of smoke big enough to have been one of the really large tear gas canisters by the doorway go off. I put my gas mask on, only to find out later that a claymore was fired into a civilian house across the road. Looked like the A team had unloaded with a M60 on the pretty concrete front.
I think either spooky or a gunship hit a house next to us when called in for support. Killed an 80 year old woman and a pig. The civilians wanted compensation for the pig but said the woman was old anyway????
Our admin officer got on an old hand crank belt fed grenade launcher once to help a small ARVN convoy that was ambushed just down the road from us. The report came back that he did more damage than the enemy.
There's probably more but I'll let them rest in the dark corners of my memory.
The point is that when I was a auto mechanic and a van broke down hauling death row inmates and the time came for them to be transferred to another vehicle, the Ruger mini 14's came out. I had so much trust in uniformed, trained guards by then that I went around to the back of the building until they were gone. I've seen nds on our club ranges and in major matches by top competitors whose name we all would recognize and once by myself with a case of tunnel vision trying to lower the hammer on a sa while hunting.
I'm not saying any of this is right or should be overlooked, but I don't have as much faith in people whether uniformed or not as what you described. And yes, you are correct though, to hold them accountable. That is one reason that it took me four years as a gun enthusiast, club president, pistol chairman, hunter safety instructor and trained range officer to apply for my concealed carry permit once my state finally allowed it. That permit places an immense responsibility upon us who do carry and I'm well aware of how things can go wrong.
Oh, and I forgot to mention the years of accident reports I've read that happen every year in the hunting fields as folks shoot at sounds or images without clearly identifying their targets first along with a host of other mistakes.