I guess I missed something here. This guy wasn't a gunman?
and if he was, more then likely he would be taken down but not shot by the guards since he was in really close range.

There would be a good chance that we would have been taken down hopefully before he could have gotten a good shot off if it was shown to have a weapon or moved to use it.

Having a gun with you can not stop someone from pulling his own weapon or doing something foolish. It can stop a person or persons if need if the threat was as bad as deemed enough to warrant taking a persons life and only then.

Nothing is 100% fool proof so "necessarily" is a moot point as far as events go. All gun owner have to justify it's use, this isn't the wild west, even if people think it is. lol

More guns may not be the answer, but no guns or less guns is NOT the soultion, THAT Fact- people are sure of,
(who understand and know firearms.)

Please see my post above for more details.
It has many good points about this kind of thing.
Be Good and be safe.