This is a really compelling story. Things are always really interesting when you have morally grey, complex characters. I like when an author can depict legit chemistry between two people who have almost no interest in the other beyond a means to an end.
In saying that, I've noticed I actually really don't vibe with masochism in stories. I've noticed I actually find the look of injuries kind of distressing and absolutely not hot. I just keep thinking about traumatic brain injuries and getting 1 too many concussions and not waking up lol.