If that were the case, then he would have made my stun gun a moot point, and I would pull my Glock 40 S&W. This isn't for those kind of situations.
Somebody threatens you with a gun, deadly force is legal where I live. The stun gun is for situations where the threat doesn't rise to the level of deadly force. Think of some drunk with a chip on his shoulder who doesn't care whether or not you want to fight.
So, how do you know that the drunk doesn’t have his own Glock 40 S&W in his waistband, and believes that the show of Taser zapping force is a threat to him?
The Taser is a weapon, just like a gun. Don’t show it or pull it out unless you are in a situation where you have to use it now. You don’t know what the drunk’s reaction will be to the zap and if he is armed himself.