I didn't understand her actions in "Comeback" at all. Why would she help Will out with the cancer patients AND triumphantly sing with the rest of the glee club, and then turn around and go, "Yeah, screw you, I somehow managed to become coach of Aurel Intensity and we're stealing your song." I mean, I get that she's devious, I get that she's a backstabber, but it just didn't make sense, and at this point she really has no reason to go after New Directions.