If 2 people make aggressive moves (open to interpretation) towards you, that is threatening with deadly force. You can draw and fire. If you are carrying concealed and one unarmed man makes threatening moves toward you, you cannot draw and fire. You can produce the weapon and and return the threat. If he continues, fair game. He was trying to disarm you and you have to protect #1.
Correct me if I am wrong. I always like to be updated.
I am old, and anyone who manaces me, has me frightened of bodily harm. So I don't think I have time to waste on their trying to disarm me, in light of their younger, faster reflexes.