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.
You two were in perfect harmony, though.
Aber ihr habt wirklich 
gut miteinander harmoniert.
Pero estaban en armonía.
Pero los dos tocabais en perfecta armonía.
C’était pourtant 
si harmonieux.
Mas vocês dois estavam numa harmonia perfeita.