You beau really has issues to risk his life and your life over some petty traffic incident. If gunfire on both sides erupted and you caught an errant bullet in the neck paralyzing you, would it been worth it?
Oh, and if he had killed the guy at a minimum he would have spent the next year in Court defending manslaughter charges since you willfully stopped and he willfully got out armed looking for a fight. Most likely would have bankrupted him in legal fees if he was not convicted (all states are different with 'stand your ground').
Ask George Zimmerman if it was worth it two years later. Guy is bankrupt, divorced and living with his parents.