This path is likely to end badly. I'm not the author of this story. He can ultimately do whatever he wants. The sad truth is that he's been very clear that Sophie cares about her teaching. There's no reason to keep emphasizing that part of her, if he wasn't setting her up for a fall. Yes, she's been cruel to Felix, but this post isn't about Felix's fate. Her teaching career and her academic integrity has been the focal point of this story.
Once, she had integrity and was a good teacher. The entire first half of the story was his persistent seduction of her . . . even as she insisted that he pass the class legitimately by learning the materials. Him passing the first class with such a high score was a personal and gratifying achievement for her. Now, by giving him the answers she's essentially thrown away her reason for being a teacher, and spit in the face of her former self. She had total disdain and disrespect for Brooks for even suggesting she just give Zack a free pass . . . yet now, she's as bad as Brooks, lying and cheating for Zack, giving him the answers for her own equally selfish reasons. Once she cared about her profession and what it meant to her . . . also evidenced in the ending for the non-NTR path early on in the story.
It's a hard NTR-sex VN, so of course much of the story has focused on her relationship with Felix and her sexual relationship with Zack. But her integrity as a teacher was a persistent theme of the story. And now, she's not just lying and cheating on Felix, she has total disdain for her other students. And cheating for Zack, is cheating on them too. It's a fairness issue that she emphasized early on in the story. She's also abandoned her other students, since she's been so busy with Zack; some of them even complained about it to her face. She just simply ignored them. All of the pieces are in place for her to get fired from her job, and lose her respectability. She has no academic integrity now, so maybe she doesn't care at this point. She's totally lost herself in Zack's manipulations. At least for this path.
Will Zack stay with her when everything falls apart? I have no idea. He's manipulative, selfish, and cruel. I can totally see him abandoning her, and moving onto his next target. Even if he loves her now, it won't last, and he doesn't have the stones to stay with her when things go terribly wrong. His pattern, evidence by things he's said in the story, indicate she is not his first rodeo. That he has done this to multiple other married teachers. He gets off on turning his prey against their husbands. Like a serial killer, he's a predator that will never be satisfied with what he has. Or at least that's how he's been written so far.
