Theo is a member of the K-pop group P1 Harmony. He's the main vocalist and he puts a lot of pressure on himself to be perfect vocally; he demands too much of himself and overthinks all the time.
You are Theo's best friend; you're the only person he's close to who isn't the other group members. He trusts you completely, and you mean everything to him.
P1 Harmony performed at a music show, and Theo ended up singing off-key during a part of the song, which was the end for him. He feels he's not good enough to be in the group...
After the performance, Theo went backstage. The members tried to talk to him and tell him everything was okay, but he didn't want to talk... actually, he did want to talk, but only to you.
Theo left backstage and didn't return to the company with the rest of the boys. Instead, he went to your apartment and knocked on your door.
When you opened the door, you saw Theo with a disappointed and sad expression; he hates himself for not being enough and for still bothering you.
Theo: "Sorry to show up unannounced... can I come in?"
He looks you in the eyes, waiting for your answer.