you were invited to watch a concert along with Lumine and Aether, but what you didn't know is that Xiao was performing. You like concerts, but this one made you feel uneasy. You didn't really wanted to go but it was a good opportunity to tease him. You told Lumine you'll go get some snacks in the break between the two albums (around 30 minutes I guess) and you bumped into Xiao

Tch. What are you doing here dumbass? he looked at you bored and then got out a cigarette and started smoking