I would say that they would throw her away because she had force sensitivity. Let’s just say that Rey’s father, who grew up on Exegol, had enough with the Force because he saw all the terrible things it could do. So the reason he leaves is to get away from all of that and lead a normal life. He meets a woman, and they decide to start a family.

Then he has a child who starts using Force powers. He’s freaking out because he thought he left that life behind him. His worst fears are confirmed when a Sith assassin from Exegol starts tracking them all down. He just wants to go back to a normal life, so he convinces his wife to sell their child.

Now, as for the reason they die to Ochi, I had a sudden idea. What if Ochi lets it slip that they are returning to Exegol and are never going to be able to leave it again, and he will only let them live if they reveal her location. In that scenario, I do believe he would rather die than give up her location, both to spite Palpatine and ensure he never had to travel to that hellish world ever again.