Opinion: Does the threat of being tased warrant using deadly force?

I saw a news article from my state about a woman that was robbed by two men with a taser. This occurred in broad daylight in a downtown area. It got me thinking, if I saw that happen should I draw and/or be justified in shooting? I know this is not formal legal advise, just curious to see your thoughts or if there are cases of this. I live a duty to retreat state. I know tasers are used by law enforcement as a non-lethal weapon, but I also know depending on a medical condition or the fact that somebody falling face first on concrete after being tased could easily kill them. If somebody had a taser pointed at me before I had time to react, like any other weapon, I'd hand them my wallet and hope not to get tased. But if I see a person (in this case a young woman) being robbed and have a safe opportunity to draw, I'm not sure how I'd proceed since it's not technically a deadly weapon. Curious to see what CCW thinks. via /r/CCW http://ift.tt/27t0FNh