When you check the etymology of the word "gahasa" it actually means to take away. "Rape" here is not just literal rape but how a woman is "raped" in our society, whether physically, emotionally, psychologically, economically, etc. The reason we used "rapture" is because we want to highlight the fact that a woman trapped in such a situation can also escape from their plight. And there is nothing wrong to have the sense of ecstasy when the woman has escaped from her dire predicament.
You have raised very interesting points. I really hope we can catch you at our CCP screenings!