You have long term crazy, then you have to time when something in the "sane person" mind flips the crazy switch.Finding the time to pre-ement and mitigate the horror is the key,although more times than not their are red flag warnings.In a perfect world,but there is no such thing.Not only here but around the world.That is where a good guy/gal with a firearm is needed to put an aburupt end to the violence.