Humans are subject to 'malfunctions' anywhere and anytime--no different than animals, computers, cars, machinery, nature etc...Things fail or go wrong all the time and unless one is clairvoyant, the location of the 'malfunction' cannot be presupposed. Once you realize or, more importantly, accept this fact you will understand the importance of always being prepared IMO. Respectfully speaking, it sounds as though you have yet to arrive at this conclusion (hence the ambivalence).
The most recent example I can think of is that dude who started shooting in NY City by the Empire State Building, and had to be brought down by the cops. Most people who knew him thought this was the last thing he would do. He'd never had any mental issues or major run ins with the law. I'm guessing his work situation came to a head and he just snapped. Moral of the story...you never know when or where.