JoelR: seems to work. It doesn't lose a tempo, because Black must play before getting on with taking White's liberties, and it costs Black a liberty. It looked odd to me at first, because it looked like White was trying to make eye that was already ruined.
unkx80: Yes.
Compare this failure diagram. And at doesn't work, because after at , White is way behind on liberties.
unkx80: Not "way behind on liberties", there is only a difference of one liberty.