I don't like such obvious death flags. And the production team is now just recycling ideas from Code Geass.
Her void was overpowered and sort of a Deus Ex Machina and she competed with Inori for Shu's attention... duh... she had a big fat bullseye.
Why couldn't they just keep her alive? Would it really be that inconvenient? These sorts of deaths are getting cliche. Too hard writing a story where Shu actually chooses a girl? In worked in Macross... it's not that hard.
She bit the bullet like Shirley.