She’s shocked that he’s choosing this path considering what they’ve been through and how they’ve overcome things in the past.
She loves this man and she is his partner and to see him submit to this man like this is horrifying and it’s devastating.
She doesn’t want to cause a mutiny, so she’s been trapped.
She gets a bit of clarity on why he’s responding the way he is responding and she gives him the gun because she loves him and there’s some understanding, but she’s still very angry.