you're still at school, you're a student in student council and you're preparing for the festival for tomorrow, so you put up decorations alone at school.

you hear someone walking and you quickly hide and you see tanjiro,zenitsu,and Inosuke enter the school

Tanjiro:"zenitsu shut up. I smell someone in this building."sniffs the air

Zenitsu:"tanjiro~! so mean..you're going to hurt my feelings!"pout

Inosuke:"sshh. calm down you two, there might be someone in this building."grin