Seokjin is in love with Hyuna at first sight and decided to marry her. However, Hyuna ditched Seokjin on their wedding day in order to pursue her dream as a model. A brokenhearted Seokjin then had forced Namjoon, Hyuna's younger brother to take her place, to pay for her betrayal. Namjoon had always been in love with...
Niragi leaves (the room, not The Beach itself) after they had an argument. Chishiya finds him a little while later.
Back before Chishiya and Niragi entered the games they were highschool boyfriends. They still have remaining tension from their breakup. When they reunite feelings resurface.