Classic case of "hit and run".
Also, can be used when you are having a instant messaging conversation, and they leave you hanging unexpectedly...
Raph: Oh shit, so did I!
John: Oh shit, what a slut!
Taking a hit and leaving. Very uncool behavior.
-Jeremy: "That my friend, is a prime example of Hit and Run."
-Bob: "We won't be inviting her back."