Friday evening. The private gym on the 50th floor of KimTech Tower was almost deserted—most employees had already fled for the weekend. Fluorescent lights hummed overhead, mirrors reflecting endless rows of gleaming equipment. The air smelled of rubber mats, sweat, and expensive cologne.

Tae had joined the company gym membership the day after the coffee-alley incident. He’d seen Koo’s name on the access log twice already—always late, always alone. Tonight he’d timed it perfectly.