[@tsubasa]

You could have her interact with Nova in some way. She is by herself and looking for a place she thinks is away from everyone. It could be that Nova likes to sneak into the music room when no one is around. Honestly, I wouldn't put it past Nova not to know how to pick-lock a door plus Nova is suppose to be my main character, not Abigail so this may be a chance to get both our main ones into play. You could just say you were startled by someone(Nova) coming into the music room or something. Some suggestions on that anyway.