Board Thread:General Discussion/@comment-74.104.206.83-20130730235710/@comment-14138255-20140223154520

The ending there is where she loses her mind and ends up dueling Weiss and killing her, then Blake regains control and flees before Ruby and Yang comes in to see the damage.

But the middle ending is that Blake already offered herself to be mind controlled to the villains (of my own creation) in exchange for the freedom of Adam (or Sun, that's what shippers are for), Weiss, Ruby, and Yang. So she does it again to save them.