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.
But I was really happy...
Aber mich hat es wirklich gefreut.
Pero estaba muy feliz...
Pero estaba entusiasmada.
En tout cas, 
ça m’a vraiment fait plaisir.
Mas eu fiquei tão feliz...