OP's approach is punitive enough and really is all you need in most situations. Although sinking to rudeness can be a natural and spontaneous manifestation of anger, it's rarely worthwhile. When facing a rude or angry person you further lose because they managed to pull you into their own personal hell.
Such disagreeable situations call for calm and playful assertiveness. You catch the opposite party off guard by politely calling them out and exposing them for being an asshole. You leaving thereafter also strips them of the opportunity to correct their immediate behavior and thus, robs them of a chance to demonstrate that it was, in fact, a misunderstanding. That can be quite frustrating, since most rude people really like to project the veil of being decent human beings and hate the idea of someone thinking less of them.
Perhaps have a harsher/rude version in case you see someone not respecting your time and are being rude.
"Folks, it's clear to me that I don't want to work here. I don't want to waste any more of my time".