There is some discussion over at Sharp as a Marble regarding the link I posted here regarding aggressors claiming self defense.

I think Rob is correct in pointing this out:

… ‘proportionate response’ doesn’t translate into the real world easily …

Using the least amount of force is generally the most legally defensible option. If an aggressor is trying to flee and you are preventing them from doing so it is pretty hard to argue that you couldn’t escape. Self defense isn’t designed to be ‘punishment’, we have courts for that. We must fight until we are sure that we can escape, and then we should do so.

Tactically speaking, if you are spending time on a neutralized threat you are creating an opportunity for another assailant. You have already confirmed that you are in the location where fights happen and we don’t know if the first assailant brought along a (tougher) friend. His friend might have been staying out of it because he didn’t want to get hurt, didn’t want to get in trouble, or thought the first guy could handle it. If the defender starts winning, that equation can change.