The potential for redemption had always been there, I had just never considered it. And it's part of our heritage. After all, we're the folks who gave Western Civilization Amazing and Astounding. Surprises sustain and even enhance the reader's interest in a developing plot. For some time after that last page is turned, the reader will still be thinking about what happened.
Surprise forms part of the philosophical underpinnings of the genre as well.
If science fiction is about things that could happen but haven't yet, and fantasy is about impossible things, then astonishment is our natural condition. Moreover, the genre has a proud history of subverting cultural assumptions and challenging the common wisdom. For example, it's entirely possible that Henry has multiple personalities and his monster is one of them. It would take a miracle to save her, and the common wisdom is that, in reality, there are no miracles, more's the pity. Actually, two miracles occur in the seduction scene and only one is fantastic.