:_( buhuaaaaaaaaaaah I can't read the spoiler, I can't read the spoiler! Please, don't post spoilers!!! I get so sad that I still can't finish my game :_(
I am happy to read everyone's opinions but please, just write opinions, no fact :-(
So I've just read your post here and there, trying to avoid facts and focusing on opinions.
I haven't finished the game yet, so my opinions are "partial", but I'd give a try to express my 2 cents that, of course, could surely change as I proceed with the plot.
Bishop is bad. Everything and everyone in his life had said to him that. And he grew up with that conviction in his mind. Evil people don't think of being evil. A serial killer doesn't consider himself "evil", a husband who beats his wife, doesn't think to be evil either. Psychology has had huge problems during years to explain this and I suppose it still can't. Who are the people who think at themselves as evil?
Usually those that, as children, have been called "evil" many times (no, I am not joking) because they develop a sort of bad image of themselves. Well, I think Bishop is affected by this sort of syndrome. He raised considering himself as evil and bad, and he simply spent the rest of his life doing 2 opposite things: from one side, he tried to "fulfil his destiny", being evil and mean; on the other side, he felt a sort of attraction to what is good.
If I am evil and I am ok with that, I don't have the necessity to "avoid" the good or to constantly point out that I am evil and that good is bad. I'd simply don't care. So, from this point of view, if he is just evil and doesn't care about being good, why escaping? You have find a girlfriend, enjoy the thing as long as you can. Where is the need for running away?
So, yes, I think Bishop feels two opposite strengths: his "evil" side that is trying to keep the PC at his same level and his "good" side that is trying to raise himself at the PC level. Maybe, in the inner part of his being, he WANTS to be good, but he's so afraid of discovering that he's not able of being good (as all those children who believe to be bad), that he prefers to run away. You know, living with the doubt of being evil, instead of having the certainty of it. Does this make sense? I hope.
So, I think that in the romance pack they had followed this path: a Bishop continuously oscillating between his necessity of showing everyone that he's evil (SPOILER like in Ember, speaking with Nya... he has no reason to state that love is futile, that love-presents are stupid, and whatever, but he liked to point out this kind of things in the presence of his own sentimental interest, the PC, that is, frankly, a quite stupid behaviour! END SPOILER), just to adhere to his "character" :-D and at the opposite, maybe unselfconsciously, trying to see if there's a way for him to walk in the patch of rectitude. So, in the romance pack you can see that, in certain moments, Bishop does good things, but tries hard to "hide" them behind an evil sense (SPOILER like before fighting Lorne, part of the OC, when he offers to fight in behalf of the PC, but saying that he "might or might not", as like he doesn't care at all of the PC life END SPOILER)
As alcoholics don't want to join AA because they fear to see that their last chance could be wasted, Bishop escapes in the end because he doesn't want to discover if he is really evil.
My confused opinion. I hope it would make at least some sense...