The conceal to carry crap is pointless to talk about in this situation. When the guy just starts opening fire there is no time to think or react to what the hell is going on it's just mass chaos.
Wouldn't have made a difference unless we are talking about John Mcclain or James bond.
I don't believe that for a second. Lots of people go through training to deal with just those situations.
From what I've read on this story, the guy walked in through the emergency exit, Through a teargas-type device, and just slowly walked up and down the aisles shooting. IF someone was carrying they could have put a stop to this. But that information hasn't been presented in any of the articles I've read or news stories I've watched.
Like this 71 year old fella who shot some punks trying to boost an internet cafe. You can see from his actions and movements that he's got training in using a firearm in that situation. He waits till the gunman is turned around, then takes action. Everyone else was frozen or shocked, and the man with training takes action.