User blog comment:Das Wunderbar/Bloody Mary - Dead or Unknown?/@comment-24557726-20140709190446/@comment-12293947-20140709205257

I don't remember there being any emphasis on Mary's hand gesture, but it might have just been a reference to her being involved with Faith's murder. The emphasis on Faith's was explained when Nerissa did basically the same thing at the end of Cry Wolf, since she had been glamoured as Faith in episode 1. It was Telltale's way of silently confirming this.

And we haven't seen any other Fable die in their true form, so it is possible for Mary to die like that.