Their Milky Way in Seoul Concert was just two weeks away, all of s are more or less ready for their solo stage but he wasn't. Leo felt that his solo stage performance wasn't good enough, as though something a part of him was missing. He wanted to show his real self in the performance but the song choice just wasn't going right for him. 

Maybe it was that unintended incident, maybe not.

Maybe it's her, maybe it's not.