the irony of the betrayal scene is that grace has actually managed to have about half of his character arc by that point and the very fact that he's saying "no" demonstrates that he's getting closer to being the brave person stratt needs on her side, just not quite close enough. he's being firm to say he's not just gonna do whatever people ask of him and he's exhibiting vulnerability and trust in a personal relationship by believing that stratt will hear and respect his answer. let us not forget that this is the man who did Try to resist getting put in the argon death cube but ultimately rolled his eyes and went "ugh kinda bossy but whatever this is okay I guess" about it. his experiences on the petrova taskforce have made him an iota stronger, and I think that's part of what makes stratt so frustrated in that scene. the book "I don't want to die" and movie "you just can’t talk me into it" lines, representing taking ownership of his desires and an unwillingness to be passive to others' wants, are both breakthroughs for him and things he would have been too cowardly to say earlier in the timeline, and she definitely knows him well enough to be able to see that. I think there's a part of her that's thinking "if you'd only done this faster and been the person who learned how to say no two years ago then maybe by now you'd be the person who's learned how to say yes."
