Board Thread:Episode Discussion/@comment-14138255-20160214165601/@comment-26397825-20160222203911

Actually, they are connecting her name with Achilles himself, not Pyrrhic Victory. Achilles was brought down in battle from damage to his one vulnerable spot; his heel. He was invincible otherwise, which ties into the nickname Pyrrha got of 'the Invincible Girl'.

The fact that her death led to a Pyrrhic Victory at the hands of Ruby's Silver Eyes is just icing on the cake, really.