[Because even if it was some ticked off kid, Byung-hee was still even more ticked off, though about what he hadn't yet decided on. He'll come up with something if the subject ever resumed.]
Why doncha pay it off now?
[Because he didn't know if he was going to meet this person again and he was willing to put up with anyone so long as there was a meal involved.]
no subject
[Because even if it was some ticked off kid, Byung-hee was still even more ticked off, though about what he hadn't yet decided on. He'll come up with something if the subject ever resumed.]
Why doncha pay it off now?
[Because he didn't know if he was going to meet this person again and he was willing to put up with anyone so long as there was a meal involved.]