Being an introvert I'm not quite sure I'd terminate the interview loop myself, but I'd probably stop trying to sell myself for the rest of the loop and start trying to figure out if I could ask questions that would reinforce that I shouldn't work there. My brain would go to the place where I was trying to teach myself how to better interview companies for their behavior--you're in a situation where you know you don't like this company, so what other data can you gather about that, and what questions could you ask of future companies that you interview at?