It really depends on the situation. If someone was getting physical with my boss, I would intervene only to break them up while at the same time instructing a co-worker to dial 911. My firearm would never be drawn unless I thought my life was in danger.
If someone got physical with me, it would really depend on the circumstances. Indiana Code requires that you feel that you are in danger of death or severe bodily damage. A black eye is not enough to draw your gun IMO, unless you honestly believe that the threat will continue resulting in severe bodily damage.
Well stated.