If you have a life-threatening situation and you have the distance and it is safe to do so, issue commands to your adversary. Issue your commands in a clear and loud voice. Give your adversary simple, yet very clear ultimatums, such as, "Stay away or I will shoot." or "Drop the weapon or I will shoot." You want to issue loud ultimatums for two reasons: 1) You want your adversary to have every chance to not be shot. Your desire is to not shoot people. And 2) You want to draw attention to yourself. You want to create good witnesses around you who can testify, that they heard you give an ultimatum. You are certainly in a stressful situation but do your best not to use profanity or issue graphic threats. Certainly, protecting yourself and the lives of your loved ones is the most important thing. If you do not have the time or the distance to issue and ultimatum, do not waste the valuable seconds. Simply, defend yourself.