I know nothing of hand guns. I agree that this may not be what I consider accidental. Guns to me are VERY dangerous and must be treated as such. Having said that i hunt and my 9 children hunt and we shoot lots. I am over cautious (maybe) but am very scared of something like this happening if I don't make 100% sure every gun in ALL situations is handled as loaded. Now a hand gun to me could very easily be dropped or slip out of your hand. My hands are 3X large. a small knife or small hand gun in my hand gives no control. If a hand gun slipped out of your hand and you grabbed it before it hit the ground could it go off? That would be an accident and may be what happened. I know of someone who accidentally shot someone in the rear through a wall. carless YES. another thought his muzzle loader was empty and fired off a primer in the house. Now has a hole in the kitchen cupboard to remind him how stupid he was. we don't know what happened here and i hope all learn and everyone that hears about it learns, and all turns out well for the family. There are no do overs when guns are involved. cut yourself with a knife, cut someone else with a knife, lose a finger, those are not life threatening as a rule, with guns it is a total different story.
Your scenario of a dropped gun and catching it is why a loaded firearm, when dropped, should be allowed to continue its fall. Under no circumstances should it be grabbed for, that is how a negligent discharge in that scenario is most likely to happen. No gun (that isn't worn out, or an antique) should fire when dropped.
And before anyone says, "But the 1911...", if a 1911 is being carried Condition 1 (cocked and locked, as intended), it won't drop fire. Yes, original 1911s will drop fire in Condition 2 (loaded chamber, hammer down, a no no in my book) most modern 1911s have a firing pin block to keep this from happening, even still, Condition 2 is not a safe carry option. The military taught soldiers to carry Condition 3 (empty chamber, hammer down), this will also prevent drop fires.
Old revolvers will drop fire if carried hammer down over a loaded chamber, this is why most carried them with an empty chamber under the hammer. Some revolvers had safety notches halfway between chambers to make them safe to carry with a full cylinder. Mid-20th Century up revolvers employ some form of transfer bar system that makes them safe to carry hammer down over a cylinder because there is a block between hammer and firing pin that only moves if the firing sequence is correct.
My EDC is a double action only semi-auto. The enclosed hammer is in a half-cock position when the slide is cycled to load the chamber. I must admit it has slipped out of my hand more than once when unholstering in the evening with no firing or other issues. But, I never upholster or clear my EDC in the company of others, so the only I was exposed to any risk.
That brings us to the Sig P320, a striker fired gun, which is known to drop fire in its original form. Those guns were recalled, and hopefully owners have sent them in for repair.
Having been a 4H firearms instructor over 10 years, when you're dealing with kids, you're going to have drops, and we've never had a negligent discharge. If all protocols are followed (muzzle pointed in safe direction, finger off the trigger, etc) everyone should be fine. This is where proper firearm training shines. When one is instructed the how's and why's with an unloaded firearm, loaded handling should be safe as well.