‘Decision to Leave’ has Park Chan-wook’s signature brutality and sexpionage, but they’ve been placed in the background, focusing instead on the tender romanticism that is as explosive as the violence Hae-joon (Park Hae-il) has trouble sleeping. He’s a detective from Busan with unsolved cases on his wall looming over his head, like the flies and ants that feast on the bodies of dead victims throughout the film. Soon, Song Seo-rae (captivatingly played by Tang Wei) enters his life as an innocuous yet alluring Chinese woman who focuses on assisting the elderly. Because of her, he finally learns how to sleep....