Interviews are a two way street and you are interviewing them as much as they are interviewing you.

Should you ever have a truly terrible experience in interview, first tell them that you are going to have to call a halt so as to not waste any more time.

Then inform them that you are very sorry, but unfortunately they have managed to fail the interview process and should the chance to employ you come around again, could they please not reapply.

Then walk away.

I have only done this once, while being told about the extra unpaid hours I would have to put in because of 'culture'.

It was more than worth it though, as I got to see a shade of maroon that I was previously unaware was even within the gamut of normal human skin tones.