You can have all equipment ready for SHTF, ammo, weapon, gear… you can even be perfectly good trained in lot of different skills and fields and still when SHTF you can end up dead in the first days just because you what i call “refuse to believe” what’s happening.
It is that state of mind when man simple do not want (or not able) to comprehend new situation.
It can be one quick life threatening situation like folks attacking your home and you just waited few seconds too long to shoot some attacker, and then you are dead, end of the story. Or it can be whole process of failing to recognize new world around you and new rules (or absence of rules) and then again you just not doing correct things for the situation, and again you end up dead.
Example would be that when SHTF you are trying desperately to have and use power generator and light all rooms in your houses just because it mean normal life for you. And that normal life is gone, and trying to bring it back in that situation usually means more troubles.
Holding onto all comforts and behavior you are used to can be dangerous.
To make long story short, what I am trying to say is that you may be trained and equip like SEAL member and still you can be killed easily from some 70 years old dude, with even older rifle just because you were surprised when SHTF with amount of destruction and violence and you did not seen that old dude coming (or being so evil).
h/t Matt Bracken