In this regard I actually wondered early on just how overwhelming this must have been. I'm no expert on ER's but I'd assume 53 wounded individuals would overwhelm the resources of most hospitals multiple times over.
I'm not an expert in ED's either, but I don't think they were overwhelmed at all -- for several reasons.
For one thing, their tweets say the real emergency was actually easier to manage than some of their drills...which is
exactly how drills should be. Second, this is not unknown territory for hospitals or EMS services -- we train for this stuff constantly and everybody knows what to do first, and second, and third, and ... Nobody needs to be told what to do -- they arrive, they look around, they jump in.
Another reason -- consider the environment of the event itself.
Initially, there were injured people outside the club -- probably the least injured who therefore were able to escape quickly. My expectation for those patients is that most of them would NOT have been shot, but injured during their escape -- lacerations, blunt trauma from being knocked down or stepped on, maybe some fractures, but nothing like the people who were shot.
As the event unfolded, additional people would have escaped or been found...and many of those would be severely injured, making it more difficult for them to get, or be brought, to care. All of those would be triaged, and as their number came up they would be transported to the most appropriate medical facility -- which often would not be the trauma center at ORMC.
And finally, it was not until three hours after the first shots that the SWAT team rescued another 30 people -- some of whom were undoubtedly injured. Then SWAT would have cleared and secured the building, probably discovering additional patients in the process.
So the patient flow would have been spread out over probably a 2 1/2 - 4 hour time period.
This horrific tragedy was very different from the Boston Marathon bombings, where the bombs went off literally right in front of dozens of first responders, with ambulances already parked right there, and within a few miles of a half a dozen world-class hospitals. Those hospitals got patients within a few minutes (thankfully!).
In this situation, arrivals at the hospitals were delayed by hours in some cases by the unsafe environment at the club.
I'm so sorry. That's really awful. 
