No matter how "right" you may think you were in a self defense situation if you defend yourself from a flash mob expect the most intense legal challenges of your life.
Certainly if you let somebody kill you or leave you a drooling vegetable, unable to care for yourself, none of the above is concern.
I realize that someone must take a stand. At the same time I urge you to RUN from these situations.
Why? I'm not going to get away.
I was a lousy runner as a 21 year old infantry second lieutenant. I'm not one millisecond faster at 53.
The State of Ohio doesn't require me to RUN from an assailant when out of home or vehicle, merely to ATTEMPT to withdraw. Virtually EVERY one of the recent violent flashmob incidents involved the victims being surrounded or trapped. The only way you're gong "run" THROUGH a mob is by shooting the members in your path.
To allow myself to be robbed, beaten, crippled or murdered in order to avoid LEGAL trouble is like allowing my house to burn down rather than soil my house with fire extinguisher residue.
Of course I don't live in Berkley or Madison. Here in Ohio, people take a VERY dim view of strongarm robbery. In fact, we've made it a practice to shoot people who engage in it. The most recent person to do so is doing just fine, facing NO legal repercussions from police and prosecutors, and BY LAW no danger of civil liability. After getting shot by the victim of your violent assault, try to find a lawyer who'll take your frivolous case on a contingent basis, KNOWING that even if you DID win, you couldn't collect a PENNY.