Rule #1 is to avoid the conflict if at all possible. World goes to *&^$ something tells me you can't call 911 (even if you win the fight) if/when you get injured. I don't think a doctor is a phone call away and hosptials might be so jammed full the broken arm you have might be a long way down the priority list.
Rule #2 Don't underestimate your opponent.
At 5'7 I have no disillusions about my ability to fight a larger opponent. I've been in two fights my entire life...one I ran from (and the guy eventually became my best friend

) the other I stood my ground and the guy just walked away..
Well I guess I've never been in a fight.
If the world goes to heck, my job is to fight as absolutely as dirty as possible to incapacitate a person as quickly as I can.
Hand, foot or whatever I can get my hands on...meet b****