I hate to sound like a sheeple, but there is no 'real' planning for this case.
IMHO, it's like planning for a meteor strike. You'll either be in the right place to help somebody, be the target yourself, have the drop, or what have you.
We can only be aware of our surroundings at all times and hopefully be able to 'do' something correctly when/if the time comes because we're always running scenarios through our minds every time we go anywhere. I do, but I also know I'm a good tight friend of Murphy. I think we're bedfellows sometimes.
Member, GoA, NRA-ILA, SAF, NRA Life Member