There's an obvious shift in the mood as Taehyung waits for Seokjin's answer. Seokjin can feel how tense the boy is next to him, he guesses Taehyung doesn't usually flirt so outright with others – because that's what he supposes this was. An attempt at flirting. A pretty good one at that, in Seokjin's opinion. Under normal circumstances, he would immediately flirt back, since Taehyung is handsome, cute and nice. But –
"Thank you," Seokjin says and looks back at Taehyung, "but I only dared because my boyfriend basically forced me to apply."
[Or: Seokjin starts a new major and meets Taehyung, who he quickly starts to like as a friend and then as something more, but that's not right, because Seokjin is dating Yoongi, and he loves Yoongi, and he can't be in love with two people at the same time ... right?]