This wording is going to haunt me.

This is what awakens Mars. I’m inclined to think it’s an echo of words she said before.

So the anymore kills me. 

This calls to a Mars who saw Serenity (and maybe the other guardians) hurt.

The moments before she transforms, Rei’s face is rage. She goes past determination and past simple anger. She feels the rage Mars felt at seeing her princess hurt. 

Rei doesn’t consciously remember the Silver Millenium yet, but the emotion is there.