But the script was bad. Never read the book so I don't know how accurate the movie is compared to the original, but damn, the girls made every bad decision you could possibly make in this scenario. Even in the thriller/horror universe!
It could have been a better movie if they explored Kim's character arc more. Now she went from being mousy to psycho with Dissociative Identity Disorder instantly. That would have been an interesting story. Missed opportunity.