No correlation?
The killer this week got off 150 plus shots (means he reloaded at least 4-5 times) and did not encounter ONE person shooting back at him (because it's against the law to have a weapon on campus).
You think mass killers don't choose soft targets on purpose?
I think he chose that location because he had some mental health issues and that place was a place that triggered those issues. He obviously had many issues there in the past.
At universities, there's whole police forces on campus that are armed, at my high school, there was always some on-duty police officers outside - I would be a bit shocked if there wasn't there as well.
Pulse for example - he chose it because of the clientele there, not because no one would have a gun. They didn't check you at Pulse prior to what happened.
The matter of fact is - even if you were allowed to carry a gun - the vast majority of people wouldn't be carrying one. They choose locations that have some sort of significance or familiarity to them, where they know they can kill a lot of people, EVEN IF someone was there to stop them pretty quickly.
Sorry - I don't think arming more people will do anything to stop these attacks - it runs WAY deeper than that.