"Shutter Island" concludes with the revelation that 
Leonardo  DiCaprio's U.S. Marshal Teddy Daniels is in fact an alternate  persona constructed by 
former U.S. Marshal and current Shutter  Island inmate Andrew Laeddis. The entire investigation that unfolds over  the course of the story was in fact an elaborate ruse designed to  rattle Laeddis so much that he puts his Daniels persona to rest. In this book, there's no question about how the ending plays out.  Laeddis, seemingly on the road to recovery after his shocking ordeal,  goes to sleep. He wakes up and meets with his doctor, who had been  playing the role of his partner for the "case," outside the main  facility. As the two sit there, it becomes clear that Laeddis has once  again lapsed into his Daniels persona, essentially sentencing himself to  a lobotomy.
 The film is more ambiguous. Things play out similarly, but as  Laeddis/Daniels sits and has a smoke with his doctor/partner, he asks  the question "Would you rather live as a monster or die as a hero?" This  raises the possibility that his relapse is in fact intentional, that  Laeddis is so tired of being sick, he longs for the blissful ignorance  that a lobotomy will bring.
 We asked Lehane for his thoughts on the altered ending in an  interview last week. "I would say that line, which comes across as a  question, he asks it sort of rhetorically," he explained. "Personally, I  think he has a momentary flash. To me that's all it is. It's just one  moment of sanity mixed in the midst of all the other delusions."
 "When he asks the question, he does it in such a way that, if he were  to say it as a statement... then there's no solution here but to stop  the lobotomy. Because if he shows any sort of self-awareness, then it's  over, they wouldn't want to lobotomize him. My feeling was no, he's not  so conscious he says 'Oh I'm going to decide to pretend to be Laeddis so  they'll finally give me a lobotomy.' That would just be far more  suicidal than I think this character is. I think that in one moment, for  a half a second sitting there in that island he remembered who he was  and then he asks that question and he quickly sort of lets it go. That  was my feeling on that line."
 That's about as detailed an explanation as a fan could hope for. It's  also a sensible read, even if you don't agree with the decision to make  the change. Lehane was and is okay with it though.
 "I liked that line when I read the script," he said. "There was just  some debate as to how much of a question it is and how much of a  declarative statement. In the end they went with it being a question,  which I think is important."