But.... There was someone armed with a firearm at the club. In fact, he was an off duty police officer who was working security. And the officer opened fire on the gunman.
Orlando Club Had Armed Security
A good guy with a gun does not always stop a bad guy with a gun - even more so when that bad buy is armed with an AR15. People watch way too much TV - they think a good guy will walk in and quickly take care of the bad guy and not even have to do any paperwork. It doesn't work that way.