I have been sitting on my "what tf even happened with Grace and Stratt" meditation for I think over a month now. (Note: I'm very deliberately movie canon only, not book.)
It truly is a matter of completely incongruous expectations between them, and some aspects of their relationship that are genuinely incompatible.
First, is that Stratt is Handling Grace.
I've frequently said that Grace was doomed from the moment he figured out astrophage reproduction, but even before that, Stratt has assigned him a minder. He's a potential asset before a necessary mechanism.
I adore Carl. Not just for the obvious reasons (he's adorable, the way he's willing to joke around with Grace, "We don't need a coupon, we're the government") but for what it says that while everyone else is packing up and putting things away, when Grace and Stratt are discussing his continued work with the PTF, Carl stops and watches.
It's impossible to shake the feeling that Carl's job is keeping Dr. Grace involved and keeping him moving. He's not just a shadowy suit from The Government. He's good at people. He knows when being a hardass works and when it won't. He indulges Grace, keeping him productive.
But he also ensures Grace doesn't get loose. Grace even points out that he thought Stratt was sending a private jet, not a literal fighter jet, and Carl acknowledges this: "I know you did." Because if Grace had time to think about being hustled onto a fighter jet, he might've had time to question what's going on, he may have spooked.
It's vitally important to the delicate narrative of Dr. Grace's tenure with the PTF that he not realize he should run, because the moment he does, he becomes a much more difficult yet vitally important part of the mission.
I am desperate to know what Carl's orders were, honestly. Because when the "you have three hours" meeting happens, Carl is silent in the background but is radiating this... discomfort-resignation-guilt-despair with just a few mournful glances Grace's way.
Second, but dependent on the first: Grace acts as an emotional safe harbor for Stratt.
Stratt is as much of a sacrifice as Grace is. She simply doesn't get sent off into space to die. Instead, she will have to live with the slow dying gasps of a planet that continues to fall to panic and desperation. There is no way her time is going to be fun.
But she has to do it anyway. There is no other choice but to be Eva Fucking Stratt, who drags the planet to a viable future by any means available to her.
But she is still a person. She needs three coffees to get through a day. She tells people to applaud when they miss the obvious cue. She has zero patience for pity parties and eagerly prompts people to get to the next bulletpoint on the list. She bought everyone hats.
The film is aggressively from Grace's POV. We don't get any flashbacks that are not explicitly his point of view and what he experienced. That's an inherently unreliable narrator, but within that context: we only see Stratt loosen her grip on herself with Grace. And not because she decides to dump it on him. He frequently prompts her to share any vulnerability she can.
And its not a lot, but that doesn't matter. What matters is she knows that Grace is aware of her interiority. He's awkward about it, but he knows its there and is willing to witness it.
He gives Stratt the space to be more than Eva Fucking Stratt. As far as we know, he might be the only one.
Finally, with all that established:
I think on some level, Stratt feels personally betrayed by Grace, just as he feels betrayed by her.
It's not fair and not rational given her handling of Grace to purposefully keep him close to the Task Force and then Project Hail Mary. The "voluntary" nature of his work has been obscured so he doesn't bother questioning it. But that means when that veil is dropped, he is shocked.
He has repeatedly given Stratt the space to be a person and has no reason to assume she doesn't see him as the same. When she decides his autonomy is an acceptable sacrifice, it's as though she's turned him suddenly into an asset. (We, of course, know there's nothing sudden about it.)
But for Stratt? She finally says something vulnerable without prompt. She asks him not to make this harder than it needs to be, to let them do it differently. And for the first time, Grace says no and denies her that and instead makes her violate his personhood.
Like a door slammed in the face or a rug pulled from under her, he takes it all away, and I really think she feels betrayed, even as she's well-fucking-aware of the power she's invoking over him. She's deciding to kill him instead of letting him die on his own terms.
They're both doomed; it shouldn't matter; it was a foregone conclusion that she arranged; still, it has to sting.
She'll never say sorry because he shouldn't forgive her anyway. They both know each other that well by now. They may be the only people who do.
