I wouldn't bet on it. It took Inno a very long time just to slap a person around that you were fucking, and Inno said anything too hard on the S&M front is a hard no, she won't budge on that. I don't know how much violence is her limit, but the meaner acts (every action in red) were only recently added after so much time had passed.
As for the final boss, who knows. Something tells me if something bad happens to you, Inno would have added something that basically let you retreat or just avoid what ever fate you would have had. I'm actually betting by that point either you can freely warp out of there (you did get the warping spell at some point), or Arthur's experiments can now just rip you out of there for a momentary retreat. It seems a bit intrusive if you can just bail on the final boss like that, but there hasn't been a boss fight yet that's really put you in a bind.