Quando eu assisti Sympathy for Mr.Vengeance, I remember a scene where a guy stops a car, pulls out a knife and makes cuts on his stomach. Ryu and Yeong-mi are shown seated in a car nearby, watching the scene. I assumed this is the spot they planned to kidnap Yu-sun, but I don't remember seeing any scene where they show how they kidnapped her. The kid's parents/guardians were there with her at that time, so it didn't make sense. Moreover, the girl later seems happy to be with Ryu and Yeong-mi. That wouldn't have happened if she was forcibly kidnapped.
Is there a kidnap scene or does the director just expect the audience to assume that it happened, without going into any details?