It isn't worth the possible jail time for me trying to be a hero if me or my family is not in direct danger!
Why would there be any jail time? You are protecting yourself or a third person from imminent threat of Serious Bodily Injury. According to the IC you are GTG.
It is COMPLETELY legal to kill a BG in an armed robbery to protect the clerk.
Keep in mind also, that you have taken the responsibility of altering the situation.
So?
YOU are not responsible for the situation that the robber put you in possibly forcing you to react to HIS initial actions.
Do you really think that you will be charged if the BG (or anybody else for that matter) is killed during HIS commision of a FORCIBLE FELONY because you chose to act?