Provinding another option is the point. CC in schools is the exact same as CC anywhere else, except people are sitting at desks. I'm not sure how many times I can rephrase this until it sinks in for you.
You want to argue against CC, fine. I still think it's silly because then we guarantee that only the badguys are carrying guns, but that's a different subject. Allowing guns 10 feet from where you don't allow them is stupid.
No, the reason they aren't allowed now on school areas, post offices, and some government areas is not because they think people shooting back at attackers will harm more people. It's because they naively think that saying "no guns!" will stop people from illegally carring them anyway.
How about the option running the fuck away instead of relying on some Gun-totting cocksucker with no Police experience as being your only line of defense?
I said it to help him prove his point actually, so then by his argument the student would have to be in the room already. Which is more than unlikely, and leaves no reason for CC. Except for that 1% of the time the student will have a gun. While gun violence/accidents in schools will probably go up because of CC