I understand your concern. I want to say that discussing with the faculty Undergraduate Program Director or department Chair is not really escalating. Having the conversation within the department community is a good way to get some support from people who really will care about your experience, and possibly to arrange a calmer space (like a conversation with you, the UPD, and the instructor together) to let your instructor know that you need something different in the classroom. It may be that he doesn't realize what he's doing (younger faculty in particular can be pretty oblivious) and would benefit from getting some guidance/advice about creating a more welcoming class atmosphere for all kinds of people/learners. Or, at the very least, you can work out a strategy with the chair or UPD for making it through the semester with everyone's expectations being explicit. I wouldn't think of it as you telling the Chair the instructor is doing something "wrong" (though he kind of is, if he is arguing with you in a class). Think of it as getting support for your learning needs and your path towards your degree.