Tom's Thinking

Before killing Dickie, Tom had the idea of actually becoming Dickie. It was interesting how fast Tom thought of the idea. It had seemed as though the entire trip Tom had been working towards this plan of action. He had been studying the way Dickie spoke, walked, and dress from the beginning however, Highsmith makes it seem as though Tom just thinks of the idea 5 moments before the murder scene takes place. It makes me question whether or not Tom, subconsciously, has always wanted to be Dickie or if that is just how it fell into place during his thought process. At this point in the novel, the reader would question how someone could pull off an act like this or would even think of it.