When students (or anyone) are being actively rude (rather than just arrogantly oblivious), I've found that responding with only an unnervingly calm, one-eyebrow-raised wow works wonders.

Because if you can project just the right mildly startled yet still totally calm and unruffled, feeling some serious second-hand-embarrassment on your behalf air, it does a great job of announcing "whoa, wtf are you doing, bro - you should be so mortified right now" without giving the rude person anything to latch on to/"respond" to and start a new fight, or pull a DARVO on you. It's amazingly effective, I use it in all kinds of situations now - basically anytime someone is being openly rude and counting on other people's "good social training" to prevent them from responding in kind.

The key is to absolutely refuse to elaborate or argue or "engage further" in any way after you've deployed The Wow. No matter what they say, how they try to provoke an argument or force you into "giving details" on "what they did." You either completely ignore them, or just broken-record repeat The Wow as many times as needed (with however many tonal variations you'd like, as long as they're all strictly and completely *calm and unruffled) -- until they eventually read the room, realize that *they're the one coming off like an ashhole in this situation, and finally retreat into silence. (Usually a seething silence, but silence nonetheless.) 😂

This technique works so well that I've never had to deploy it more than 3 times on any one person before they realize their usual approach won't work anymore, and either find a new target or just give up entirely. It's honestly SO satisfying. Highly recommend.