I swear my lecturer is gaslighting me
tldr: i asked the lecturer whether we need to revise a certain topic, and he is denying we ever studied that topic
I am studying a medical physics course, but we had one lecture where the lecturer started going into detail about the hole in the ozone layer, and research he had completed about the reaction kinetics of ozone depletion - stuff that is completely unrelated to medical physics, and not at all what i signed up to study. I was so confused about why we were being taught this that i literally messaged my friend in another class about how confused i was that we had just spent the last 45 minutes learning about this completely random topic.
I forgot all about this, but now that I am revising for exams, I wanted to check with the professor about exactly what we need to memorize for the final. So I emailed him about this, and he responded saying "there was only ONE slide ... talking about the cosmic rays (ionizing radiation) and CFCs leading to the ozone hole, which was given as one of the three specific examples of ‘Respiratory burst’ ... To my understanding/judgement, this is not improper. " (emphasis is directly from the email).
He linked the lecture notes pdf for that lecture, but i swear it has been changed because in my handwritten notes i literally have 3 full pages of detail on the specific reaction pathways he covered. He even CC'd the department teaching chair in. Like, i made no insinuation that his teaching was improper, only that I couldn't understand the logic behind why he taught us this. And now i feel like i am going insane because what? I can't have imagined an entire lecture right??