The "elite student in music room 2" turns out to be Haruki's delinquent classmate, Kazusa Touma.  With his characteristic pushiness, he tries to get her to join the light music club.  But his pushiness backfires, and only makes her more annoyed.  Setsuna gets irritated... no, involved, and approaches Kazusa secretly.
That has nothing to do with your band!
Das hat absolut nichts 
mit deiner Band zu tun!
¡Eso no tiene nada que ver con tu banda!
¡Eso no tiene nada que ver con tu club!
Ça n’a aucun rapport 
avec ton club !
Isso não tem nada a ver com sua banda!