This was the title of an interesting article in the 2005 August issue of Combat Handguns. The subtitle is "A hard look at a dangerous concept!" and was written by Chuck Taylor.
As suggested by the title and sub title, the article addresses the tactics that are available when the first two shots don't work. I thought it was a very good article. I don't normally rely on gun mags for training advice, but this particular article agrees with training and tactical advice I learned at Gunsite.
It's worth reading.