I have to agree. You'd be pissing yourself if the criminal broke in with a gun (not sure how you'd know that, but let's play along) and you didn't have a gun. On the other side of that, you are on your own turf. You know all the places you can be in your house to see the criminal and they are in foreign territory (unless of course they own or have lived in the same prefab house in some rubber stamp community.)
Life is not a videogame. If someone is going to rob your house, A) statistically is far more likely to be someone who know, and B) they're probably going to do it when you're not home. But let's suppose for a moment that they do break into your house when you're there. Guy's standing in your living room, pointing a pistol at you. Is your gun in your pajamas? Probably not. You move for one of your prearranged stockpiles. He shoots you in one third of a second. Unless you're going to walk around your house with a gun duct-taped to your palm, it's not going to change anything.
...several armed defenders fighting to survive, all but one of whom (or all if the first victim is unarmed) will have a chance to return fire and limit the casualties of an otherwise much deadlier rampage.
Yes, when I think "defusing a violent situation", the first things that comes to mind is "crossfire". You're trying to dress up what's really happening - a bunch of idiots with metal penises imagining themselves as the lead role of an action movie - in this formalized language of a military encounter. In the real world, where people are not expecting a gunfight to break out at any moment, everyone in the room but the guy who broke in are going to be flatfooted every time. The first guy to resist loses his head, then there's a shootout where maybe the original perpetrator goes down, taking several with him. What exactly has been prevented that a locked door and better campus security would not?
Allowing people to carry concealed weapons just makes it that much easier for someone who wants to commit a crime to get the drop on someone else. I hate to break it to you, but allowing concealed carry on campuses will not turn the student body into a SWAT team. It will mean maybe a dozen guys will strut around campus with Colt .45s they've never fired, just waiting for someone to start trouble so they can save the day. Your bullcrap about frat boys taking training is the most laughable thing I've heard in the whole thread.
This whole conversation is an unending litany of machismo masquerading as expertise. By definition, all statistics on gun violence, or crime prevented by gun violence, is anecdotal. Mostly anecdotes made up by people who want to sound tough, in studies funded by people like Wayne LaPierre who watched too many old westerns and think the solution to urban crime is to turn America into Yemen.