Frankly, I think this tragedy can be attributed entirely to the liberal/leftist attitudes toward mental health, that have been enshrined in our laws. Gun laws of any sort had virtually nothing to do with this. He was going to kill as many people as he could by what means he could manage to. If he’d had trouble getting a gun, or had just chosen a different method, the basic outcome would likely have been the same: lots of innocent people dead. Imagine if he’d chained all the exits to a dorm shut in the middle of the night, and started tossing gasoline-fueled fire bombs through the windows? What were the rudely awakened students going to do if they had guns? Shoot the flames?
Your scenario justifies the University mandating the installation of fire-extinguishers, sprinkler systems, and window fire-escapes. Similarly, the University should mandate self-defense classes including qualification for concealed carry permits. After all, "its for the childrun".