Finally, an example of guns being used in self defense. Though by police officers at a police station, and only after three of them were shot... by a man who grabbed one of their guns:

Three New Jersey police officers were shot early on Friday at their police station, and one was in surgery for his wounds, a hospital official said.

... "A violent struggle occurred while the suspect was being processed," Gloucester Deputy Police Chief David Harkins said, according to Philadelphia TV station NBC10. The man was able to grab a gun and then opened fire.

The gunman was killed by police during the confrontation, Gloucester Police Chief W. Harry Earle said, according to the NBC10 report.

I'm not blaming the officers. Shit happens. But if a trained police officer can be shot with his own gun, imagine how often that happens to untrained civilians.