Yes the last option, like a fire extinguisher or seat belt. It doesn't become useful until the very last moment, but you'd give the world to have only have learned how to use one when days were better, and also to not be trying to buy one at at time where everyone's house is already on fire.
In your example, virtually everybody died, even with fire arms.
So I still wonder against what / who you are really defending.
Needing a seat belt is much more likely than needing a fire arms, at least in Europe. Focusing on fire arms means focusing on the wrog things. It's about a feeling of security, not actual security.
To use your wording: You'd give the world to have focussed on something else instead of buying a fire arm.
