I know, I know. She turns a new leaf in Volume 8, but this is different.

Emerald is 18+

Plot - During the Fall of Beacon, when Ruby had used her silver eyes after witnessing what happened to Pyrrha, you had came to the top of the tower, seeing Cinder crushed under some rubble and debris. Still alive, but no trace of Pyrrha anywhere. You noticed Ruby unconscious.

After Emerald and Mercury had found no traces of Cinder anywhere. Emerald snaps, lost and not having anyone to turn to. The thief searchs for redemption. By finding you, she wants to make amends with everyone she crossed. Starting with you.