How the hell did one guy keep shooting continuously for 20 minutes?

[HooptieWagon]

18. That would be my guess.

Also, peep might be under the impression it was an automatic weapon. It wasn't...one trigger pull fires one bullet, there could be several seconds between shots, so an interval to load a fresh magazine wouldn't be noticed.

The two things Im still confused about are first, that he entered the club apparently with all his arms. No one noticed? HD then went back outside, where he first exchanged fire with police officer handling security. Why was the cop outside, not inside?
Secondly,it appears there was a 2-3 hour period with the gunman inside and the cops outside. I understand about securing the perimeter, letting people escape, snd formulating a plan. But that seems like a long time. Was the gunman killing people during that time? Were the cops attempting to negotiate him into surrendering? Hadn't seen those answers addressed, understand its early in investigation and reports have to be written to get full story.