I'm having troubles with the beginning, we all know what the ending should be as explained perfectly here
But I simply cannot get my head around the fact that he arrived to the island on a boat if it was a role play. Why would they start this role play on the boat? Maybe he really was an agent and they did succeed in making him believe he killed his own wife. For me the whole boat scene is a give away to him actually coming there to investigate, but than again some things in the movie wouldn't quite make sense...
So should i just accept it that before the first scene, they got on the boat from the island, drove around a bit and then the first scene starts showing them arriving at the island? Or is there any ground for my suspicion?