I agree with you for the most part, but honestly for this one it makes the most logical sense for me for her to not escape. She only decided to do so because she would've died otherwise, but now that the Duke is awake, the situation is completely different.
Maybe I'm just desensitized from reading so many of these stories it's been a while since I felt so strongly about wanting the FL to escape/follow her original plans but seeing the story not go that way, I might've just come to accept that this is how these tropes go.
But again, I'd argue that this one is at least doing a better job of it imo? The original threat has been dealt with and the FL is very much of aware of it, making it more off for her to still want to run away without more concrete plans or trying to negotiate with the ML.
If I was the FL, I'll runaway. I want a FL who just runs away lol she carried this manhwa hard. I liked her personality, though her appearance is so common. She looks like FL in Seducing the Villain's Father.