Gun control won't do anything. If you're in a situation like this, you'd rather have a civilian armed and protect you than wait for police.
Yes it will. Notice how almost all the shooters involved in these killings are either mentally deranged or unstable in some way? Harsher and stricter guidelines on purchasing firearms would prevent people like them from buying them - the easiest way to get a firearm. Background checks and mental health evaluations are designed to do just that. Less psychos with easy access to weapons, less killings. Simple arithmetic.
It's not like you can just walk out on the street and get one off the black market from some shady guy in a trench coat. That's simply not true.
Anyways, the shooter used semi-automatic hand guns with extended magazines. Firearms that are designed for military and paramilitary use only. Are you a soldier or in the FBI? No? Then you have no need to own one.