Yukiko Koyama (Room 502) exchanges morning greetings on the balcony with Suzuki (Room 503). This greeting serves as their signal, and once both are ready, Suzuki visits Yukiko's room. As they become absorbed in sex without exchanging words, a phone bell rings. The caller is Kurokawa from Room 501. However, Yukiko doesn't mention it, and Suzuki doesn't pry. That's because their relationship is purely physical. Then, in the afternoon, Yukiko heads to Kurokawa's room. Yes, Yukiko is having a physical relationship with the men living on both sides of her.