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.
For cutting you both off earlier.
Dass ich euch beide vorhin unterbrochen habe.
por interrumpirlos antes.
Antes os interrumpí.
j’ai interrompu votre conversation, 
tout à l’heure.
Por interromper vocês dois lá.