A big difference between the GLOCK, XD, or ParaOrdinance LDA and a revolver is: the hammer of the revolver is not cocked. The hammer of the others is partially cocked, but not enough, in theory, to detonate the primer.
Basic idea: In the absence of a separate safety, the harder you have to pull on a trigger, the less likely you are to have a negligent discharge.
For purposes of argument, let us say that it is 1/3rd cocked. The trigger on these others normally pull with about 5 lbs pressure. The revolver trigger has to fully cock the hammer, and so takes 8 to 11 lbs to fully cock. The Glock has a NY Trigger option that pushes the trigger pull up to 8 lbs.
I have a Cobra Arms derringer in .38 Special, and it has a 14 pound trigger. With no trigger guard, that is just about adequate. Fortunately, it sits safe in my safe, empty.
I had my ND when I was 20, with a revolver with a 12 lb trigger. It is not the kind of thing you ever want to repeat.
I don’t know what make & model pistol was involved here, but odds are the gun was being played with, and the trigger got pulled.
As far as action designs, IMHO they should be using DA/SA autos equipped with hammer block safetys. These can be carried loaded with one in the chamber and the hammer down, safety on. In this condition, even pulling the trigger and dropping the hammer wil not fire the gun.
When needed, just push the safety off, and pull the trigger.
The Para LDA has a triple safety. The hand grip must be depressed to pull the trigger. The slide safety has to be manually switched to pull the trigger. And finally the internal safety disconnects the firing pin (unless the trigger is pulled) and this prevents a discharge if the weapon is dropped. Also the LDA has a true DA trigger with a very long pull like a revolver. It is unlike the DA on other semiautos.