Megabox COEX is a cinema near Exit 7 of Bongeunsa Station, connected to COEX and Starfield. It has recliner seats in The Boutique and a 4D theater, plus a space with a big screen where you can drink coffee while waiting. Tickets can be booked at kiosks, and showing a physical ticket allows entry 10 minutes before the screening. The Boutique seats are comfortable, but the viewing cost is high.