Well I've heard a couple of different things about the bathroom, so I'm waiting to hear when that is all settled.
The timeline I saw said the SWAT team didn't go in until 5 am, after breaking through a wall. There may have been a couple of officers inside, I do know he got into a brief gun battle with an off duty cop outside and that police arrived quickly. My issue is that the guys capable of ending it, the SWAT team, were standing down when this is what they train for.
The shooter stopped shooting a couple of times but was still an "active shooter" and history tells us guys that do this are planning on going out in a blaze of gunfire killing as many people as they can on the way out. They could have prevented death and injury.
I was talking to a coworker who's father is LA Country SWAT, he was talking to me about how they move very slowly through houses. The military version of clearing houses is very fast, overwhelming the enemy with violence, etc, but SWAT is totally different. When the military clears a house there's split seconds of having your back exposed without someone covering it as the point man goes in, and the second man goes the opposite way. SWAT however goes through a really slow weird thing with a man high, middle, and low, facing all ways. The way he described it was that it was like a flower blooming, and everywhere is covered. The reason behind that is that SWAT can't afford to lose anybody, where the military can.
Movies tend to show the military version, quick, but SWAT moves very slow. He said he was playing a hostage in one, and it took them 30 minutes to clear a small one bedroom apartment to get to him. So a club with multiple areas at night would make sense it would take them so long to clear everything except the bathroom, to ensure there wasn't more shooters.
Additionally I heard that some civilians may have been hit by police fire as well, but without more information it's hard to say.