After being seriously injured by the Nephilim, Hibiki is unable to control her Symphogear.  She flies into a rage, destroying the Nephilim and ripping out its heart.  During the post-fight medical exam, it's discovered that if she continues to use her gear, she'll die.
Episode 6 
A Miracle Is a Cruel Thing
الحلقة 6 
المعجزة هي شيءٌ قاسٍ
Episode 6
Wunder sind grausam
Episodio 6 
Un milagro es algo cruel
Episodio 6 
Un milagro es algo cruel
UN MIRACLE – C’EST UNE CHOSE CRUELLE
Episodio 6
Il Miracolo è un'Impronta Crudele
Episódio 6

Milagre - Esse é um Rastro Cruel