I haven't played Shadowlands, but I've tried to follow along.

I think there's a reason she kept trying to convince Anduin to join voluntarily. Not bc she was never given the choice. She didn't want Anduin to be forced and controlled, bc that puts Anduin under direct control of the Jailer. (She consistently goes against the Jailer's opinion of just controlling him directly multiple times, saying "he'll be more focused and they'll have better results if he joins willingly.") She knows they will eventually have to turn on the Jailer, and Anduin not being in his direct control is key for when that happens. She looks at Anduin at the moment she knows that she has to turn on the Jailer. She's immobilized, then the Jailer and Anduin both leave, and she's in real trouble.

The next step is to save Anduin, and she'll convince the others that they won't succeed in doing so w/o her help.

That's my theory so far.