"They'll harm themselves because they wont want to be seen to give us a fair ride, it could breed unrest in the cells."
Given you can't define fair, that looks like a statement of starting perspective to me. EDIT: I asked you what you viewed as 'fair' and got a reply about having to see what they offer.
As for what Fumble meant, I'll leave him to answer that. The EU will not be looking to screw the UK; they will want the UK to not be bloodyminded in return, and have a 'no deal' situation which is worse for both sides. The deal made will be fair, as it usually is in this type of thing.