NecRock?: As far as I can tell, the double atari with kills. Black threatens to capture with a play at b, thus falsifying this eye. Capturing with a play at a fails because of the snapback. Trying to save the marked stone with a play at b fails because of the connect-and-die.
White can try to resist this way, but after a throw-in with at , White still loses her eye.
unkx80: Correct!