The "Inception" ending dominated movie headlines in 2010, but "Shutter Island" opened months earlier and had a similar last moment that continues to perplex.

The last shot of “Inception” is widely regarded as one of the best ambiguous endings in movie history. Christopher Nolan leaves Dominick Cobb’s totem spinning so as not to answer whether or not the character is still dreaming. The “Inception” ending continues to stir up conversations a decade later, but it was not the first DiCaprio movie of 2010 to conclude with such an open-ended jaw-dropper. Cut to February 2010, in which Paramount were gearing up to release Martin Scorsese’s psychological thriller “Shutter Island,” based on Dennis Lehane’s 2003 novel of the same name. The movie opened February 19, 2010, making this month its 10th anniversary. “Shutter Island,” the fourth collaboration between Scorsese and DiCaprio, was a box office hit with $295 million worldwide, the highest grossing Scorsese release until it was surpassed by “The Wolf of Wall Street.” While “Shutter Island” did not go on to have the awards success that the director and actor’s other projects did, it has continued to endure over the last 10 years because its blindside of a twist ending that both rivals and predates “Inception.”

“Shutter Island” stars DiCaprio as Edward “Teddy” Daniels, a U.S. Marshal who is investigating a psychiatric facility on the eponymous island after a patient goes missing. Only Teddy is not a real person but a delusion created by inmate Andrew Laeddis. The ending of “Shutter Island” reveals that DiCaprio’s character is a patient himself, committed to the Shutter Island facility after murdering his wife (Michelle Williams) because she went insane and killed their children. Two doctors, Dr. Cawley (Ben Kingsley) and Chuck (Mark Ruffalo), created a roleplaying game (the film’s central mystery) in an attempt to break Andrew free from his delusions. The bait-and-switch twist forces the viewer to re-contextualize the entire film up until that point, making “Shutter Island” a rich experience on the second and third watches.

If the “Shutter Island” ending ranks as one of the best twists of the 21st Century, it’s one of Andrew/Teddy’s ambiguous final lines that continue to make it such a haunting and satisfying experience. Several months before DiCaprio and Nolan unleashed the spinning top in “Inception,” DiCaprio and Scorsese dropped this line of dialogue in “Shutter Island”: “Which would be worse: To live as a monster, or to die as a good man?” The line is asked by Andrew/Teddy, and in doing so Scorsese and screenwriter Laeta Kalogridis leave the door somewhat open as to whether or not Andrew/Teddy is committing himself to a lobotomy in order to wash his mind from the sins of his past. It’s an integral tweak from Lehane’s book, which ends more conclusively as Andrew slips back into his Teddy persona. The question Andrew/Teddy asks in the film makes it a possibility that the character has become more sane and is making an active choice. If Andrew is sane, then committing himself to a lobotomy because he can’t deal with the monster he’s become turns “Shutter Island” into a haunting tragedy.

Lehane approved the line during the film’s script process and told MTV in an interview a couple weeks after “Shutter Island” opened in theaters that to him the question is just a “momentary flash” of sanity within Andrew/Teddy’s delusion.

‘If he were to say it as a statement [and not a question], then there’s no solution here but to stop the lobotomy,” Lehane said at the time. “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.”

Lehane has one perspective on how the question shapes the ending of “Shutter Island,” but fans have been debating for the last decade whether or not Andrew/Teddy was a willing participant in his demise. Neither Scorsese nor DiCaprio have given interviews fully breaking down the “Shutter Island” ending, which means it’s a conclusion that will stay ambiguous for decades to come.

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