You may recall that in one church shooting here in the U.S., a man with a gun chased down the shooter and is credited with saving a lot of lives (although many were dead already in the church). Just imagine if that man with the gun had been inside that church when it got started. He could have saved many more lives. People who are anti-gun always want to convince everyone else that making it a gun free socieity is the solution to the problem of mass shootings. Perhaps they could explain why, in previous generations where there was viturally no restrictions on guns or gun sales, there were no mass shootings. Is there more mental illness? More hate? Guns are not the problem - we have a societal problem that no one wants to address, other than to ban guns. And the sad part is that you will never legislate behavior with restrictions. Look how many people are killed in accidents in our local area when they are thrown from their car and weren't wearing their seat belts, but seat belts are the law. Drugs are against the law, but every week there are arrests for drug crimes. Car accidents kill people, but no one is suggesting cars be banned. If you consider the population of our country, mass shootings are few and far betwen in the overall population. If the media didn't immediately run there and blow it up, there would be no calls to ban guns.
I'll take my chances any day with a good guy with a gun, even if I am shot accidently. Because I will know that he didn't mean to shoot me, but the bad guy with the gun is definitely out to get me.