LAST EDITED ON 10-29-11 AT 11:53 PM (EST)I'm not saying I have any proof of it, as I said above it is based on an assumption that Cochran is not making a stupid move.
Secret Agent play: Well, it might work, it really shouldn't, but Cochran's been given that mission so that is what he has to do. Since he is forced to take action and play the game, he does. There is no risk in the secret agent play, the worst case scenario is simply that it just doesn't work. This is what the Cochran you see would do, no more and no less.
Double Agent play: Cochran defects to Upolu. Not risky, it is basically game suicide; even if he gets to Final Tribal he won't win. But this play doesn't get him to Final Tribal, it moves him from #6 in Savaii to #7 in Upolu, he gets less time in the game. In fact his usefullness to Upolu is done after one vote, they could decide to end his game with the next boot. The only reason to do it, other than revenge, is if it is a ploy in a greater scheme.
Triple Agent play: Build a cross-tribal alliance to take control of the game. Cochran has Jim and Dawn to help him think it up and try to make it happen, and Jim may be the one to come up with it. So Cochran has support in this play, he's not taking the risk alone. If it works the worst case scenario is Cochran himself ends up #6 in the Secret Alliance, exactly the same spot he had in Savaii.
Why try to get the "weak" players to form this cross-tribal alliance? This is extended speculation at this point. But the "weak" players have done well to make it to the merge, the pressure is off, now they have to consider how they can get to Final Tribal and possibly win. None of them have been considered possible winners within their tribes, they are simply useful to the power players, expendable when the time comes. A cross-tribal power alliance improves all of their chances because it puts them in control of the game.