And let's not forget that the saboteur is still unknown. Might as well be Ariel.
I'm glad You mentioned that. Storywise, I think it's probably the most important thing to keep in mind, while going into relationships with girls aboard the Endurance. You cannot truly open up to anyone, because you don't know who will stab you in the back, if you trust them. I don't think there were any real hints about the identity of the culprit, and we cannot even say for sure if the culprit is there in the first place. Since the MC was transferred to the Endurance midjourney, then that's clerly a combined effort involving a lot of people. Some of them may have stayed on Earth, and some may be waiting on Elysium for the MC to arrive. And since Pandora was able to remotely access Paige and put that failsafe on her, then even she is a suspect, since she knows about everything.
I don't know who other players think the culprit may be, but I keep thinking about it and I believe it could be Sasha. She quickly established a close relationship with the MC, but putting aside their usual banter, there doesn't appear to be much emotional involvement between them. It would be reasonable to assume she's hiding something, and that she keeps MC at a certain distance, to avoid letting any info slip out in front of him. Also there's not enough info on her to just accept she's competent in leading others, yet she's always involved in helping Ishani and Umiko in making decisions about things happening on the Endurance, and she willingly helps with putting back the database together, which helps her gain info on everyone aboard, and we all know that knowledge is a powerful weapon.
I know I'm ranting a bit, but english is not my native language, so I can only hope I make sense, with what I'm trying to say.