...you don't supposed Ben's "loose end" was killing Penny (as he threatened to Whidmore) before heading back to the Island do you? If so, that would explain why Desmond goes back.
That would royally suck if true, by the way. The Desmond/Penny thing was the one part of the show I was really hoping had come/would come to a happy ending.
Damn. I'm sort of watching the "pop up" re-run of last week's episode and they just said the "loose end" was Ben's promise to kill Penny. Hope he didn't succeed.