Things You Only Notice In Shutter Island After Watching It More Than Once

Released in 2010, "Shutter Island" remains one of the strangest entries in Martin Scorsese's expansive filmography. After a string of dramas, Scorsese teamed up with frequent partner Leonardo DiCaprio to make a neo-noir psychological thriller based on the novel by Dennis Lehane. Scorsese had been of great help in DiCaprio's transformation from a child star to an acclaimed adult actor, and Shutter Island was another winning entry on their list of collaborations.

As for the plot, the movie follows two U.S. marshals, Edward "Teddy" Daniels (DiCaprio) and his new partner, Chuck Aule (Mark Ruffalo), who are called to a hospital for the criminally insane. Named Ashecliffe, the institution is located on a remote island, one where the marshals are investigating the disappearance of a mentally disturbed patient named Rachel Solando (Emily Mortimer) who vanished under mysterious circumstances. But Daniels quickly becomes aware of strange forces at work in the hospital, leading him to suspect the staff, the patients, and even Chuck. And amidst this atmosphere of paranoia, there's an even deeper mystery surrounding the identity of a man named Andrew Laeddis, who Daniels is secretly after.

Thanks to its twisty nature, "Shutter Island" belongs to a rare group of films that you can watch again and again and discover something new each time. And if you want to dig even deeper into Ashecliffe's mysteries, here are some details you might've missed the first time you watched the film. (Be warned — there are spoilers ahead.)

While crafting the creepy world of Ashecliffe, Martin Scorsese knew it would be key to select the right music in order to create the required tone and atmosphere. And as "Shutter Island" begins, cinephiles with a sharp ear for music might experience a callback to one of the greatest horror films ever made, Stanley Kubrick's "The Shining." That's because the start of "Shutter Island" makes use of an eerie song by avant-garde composer György Ligeti, one named "Lontano", which featured in "The Shining" during several tense moments.

Clearly, Scorsese wanted to make it clear to his audience right from the start that this wasn't going to be one of his usual dramas but instead a film that was a little bit closer to the horror genre than "Goodfellas" or "Raging Bull." And as the movie progresses, it skillfully uses more creepy compositions to make the audience a part of Daniels' descent into madness and paranoia.

The hospital that Daniels and his partner are called to investigate is filled with disturbed individuals who've all committed serious crimes of one nature or another. Although the audience doesn't spend a lot of time with most of the criminals, we do hear one of the inmates housed in Complex C whisper a particularly chilling line: "Stop me before I kill more."

While the line is disturbing enough on its own, what makes the whole thing even more ominous is that it's most likely a reference to a real-life serial killer named William Heirens who was active in Chicago in the 1940s. At the time of his crime spree, Heirens was known as "the Lipstick Killer", and after his arrest, he became one of Illinois' longest-serving prisoners, having spent over 65 years in prison.

The line from "Shutter Island" is a slightly altered version of something Heirens had written in lipstick on the wall of the apartment of one of his victims: "For heaven's sake catch me before I kill more I cannot control myself." The implication seems to be that some fictional version of the Lipstick Killer was residing in the hospital at the time when Daniels and his partner were conducting their investigation.

One of the biggest twists during the unexpected climax of "Shutter Island" comes with the revelation that Teddy Daniels' partner, Chuck, isn't a U.S. marshal but a psychiatrist at the same hospital that the two are supposed to be investigating. While this twist caught many off guard, the movie actually does a good job from the start of letting you know Chuck isn't who he says he is.

At the start of the investigation, the marshals are made to hand over their firearms. When it's Chuck's turn to do so, he clearly has trouble handling his gun, as though he's not used to carrying a weapon. A quick shot of Daniels' face shows he's also surprised by his partner's clumsy fumbling with the gun.

Later in the film, Daniels is interrogating Peter Breene (Christopher Denham), and the situation soon starts to get out of hand. At one point, Daniels' constant scratching on his notebook antagonizes the patient. This causes a physical altercation between the two, and Chuck pulls Daniels back to his seat with his left hand. But at the same time, we can see his right hand motioning towards the hospital staff to return Peter to his ward. Clearly, despite seemingly taking a back seat during the scene, Chuck was in charge of the whole situation.

Throughout the movie, an atmosphere of unease rests over the hospital. For example, at one point in the film, Teddy Daniels bluntly notes that a few of the guards seem nervous, to which their escort replies, "We all are."

At the time, the implication is that their nervousness is over the missing patient and the fact that the hospital is being investigated by government officials. At the end of the film, however, the true meaning of that line is made clear when it's revealed that Daniels was actually a patient at the hospital himself, who was being allowed to live out his fantasy of being a U.S. marshal investigating a case, all in the hopes that it would force him to come out of his paranoid delusions and accept the truth of his tragic past.

Thus, when the guards say they're nervous, what they're referring to is the fact that Daniels — who's confirmed to be the most dangerous patient in the entire hospital — has been given free rein to move anywhere on the island with minimal supervision, where the only person who can hope to control Daniels in this state and snap him out of his paranoid fantasies in an emergency is his partner Chuck. So yeah, their jitters are totally justified.

The most immediate source of disquiet in "Shutter Island" is the host of criminally insane patients who are being treated at the hospital. As expected, the behavior of the patients towards the two U.S. marshals is strange from the start. But the strangeness makes a lot more sense when you realize the two feds are actually Chuck, a psychiatrist, and Daniels, one of the hospital's delusional inmates.

One of the first patients that Daniels encounters waves to him with a laugh. Another one raises a finger to her lips conspiratorially. While this might've seemed strange to Daniels (who'd convinced himself that he really was a government agent), it was probably pretty humorous from the perspective of the inmates. After all, they were watching one of their own play dress-up while the hospital staff went along with the entire farce.

So it's quite logical that the whole situation of Daniels searching so seriously for a patient who never existed would've seemed funny to the other patients. It's also possible that the other patients were coached by the doctors and guards beforehand about what to say and do when Daniels interrogated them, which is why some of them behaved as though they were hiding a big secret.

In addition to the music and the performances of the supporting cast, another clever way in which "Shutter Island" makes the audience feel a similar sense of confusion and disconnect from reality as Teddy Daniels is by making deliberate mistakes in the presentation of certain scenes.

For instance, when Chuck and Daniels begin their investigation on the island, the guards are supposed to be looking for Rachel Solando, but they're actually just standing around. This is because they're not really looking for Rachel ... because Rachel doesn't exist. In another scene, Daniels watches a woman take a drink from an invisible cup, only for a glass to appear in the very next scene. Weirder still, we see Daniels' wife wearing a cardigan, and that same exact sweater is worn by a patient at the hospital.

Even the line that Daniels keeps hearing in his dream — "Why are you wet, baby?" — gets the order of the words changed when its later spoken by Andrew at the lake as he confronts his wife, becoming, "Baby, why you all wet?" The point of all these "mistakes" is to establish the fact that Daniels/Andrew is an unreliable narrator, and the audience can never be sure what's actually real and what he perceives to be real.

The scene at the lake is the most pivotal moment in the whole of "Shutter Island." That's the moment where Teddy Daniels/Andrew Laeddis realizes that his wife has murdered their children, kicking off his descent into mental instability that ends with him becoming a patient at Ashecliffe hospital.

That scene occurs before the start of "Shutter Island," but we witness the horror via Daniels' traumatic flashbacks. To underscore the otherworldly nature of that moment, in which Daniels realizes he's actually a mentally ill man named Andrew, certain parts of the scenes are shot in reverse and inserted among the regularly shot scenes.

For instance, when the scene cuts to Daniels smoking a cigarette, if you watch closely, the smoke is going into his cigarette instead of coming out of it. Similarly, his wife, Dolores (Michelle Williams), can be seen walking backwards away from the lake in another flashback. Using this reverse motion effect produces a dreamlike state in the narrative, where the audience can sense something is off about the scene even if they can't pinpoint exactly what it is. This is exactly what Andrew himself feels when he comes home to find his children missing and his wife behaving strangely before slowly realizing the horrifying truth.

As we find out near the end of the film, everything we've seen in "Shutter Island" has been an attempt by the Ashecliffe hospital staff to break through Andrew's delusions by allowing him to playact the role of U.S. Marshal Teddy Daniels. And in the final moments of the movie, we discover that the treatment has worked, at least for a bit, and Andrew remembers his true self. But as it turns out, we actually get a hint much earlier in the film that the treatment is bearing fruit.

While pretending to be Daniels, Leonardo DiCaprio's character believes that an arsonist named Andrew Laeddis killed his wife in a fire. Since Daniels' mind is trying very hard to convince himself that he is not Andrew himself, he's unable to strike his own matches for cigarettes. After all, in Daniels' mind, fire is inextricably linked to Andrew, so it's something to be avoided.

However, later in the movie, we see Daniels start to strike his own matches, hinting that he's starting to accept the truth about his relationship with Andrew, revealing that the treatment is indeed working.

All through "Shutter Island," the lighthouse at the end of the island represents the twisted nature of Ashecliffe hospital and the paranoid delusions of Andrew Laeddis. In his role as U.S. Marshal Teddy Daniels, Andrew convinces himself that the hospital uses the lighthouse as a remote place to carry out forced lobotomies on their patients in an effort to unlock new mind-control techniques. 

In this delusional state, Andrew swims to the lighthouse, knocks out the guard, and enters the lighthouse to confront the hospital's lead psychiatrist, John Cawley (Ben Kingsley). And yet, when Andrew is at the lighthouse, his clothes appear completely dry instead of being soaking wet after all that swimming he was supposed to have done.

Since we later find out that Andrew is a patient at the hospital who's only been imagining the dangers and conspiracies taking place at Ashecliffe, it's quite likely that he imagined a more dramatic method of getting to the lighthouse than what actually happened. After all, Cawley wanted Andrew to come to the lighthouse and had no reason to make the trip unnecessarily difficult. Thus, Andrew might've simply taken a boat to his final destination while imagining he had to swim across stormy seas to get there.

Dr. John Cawley is the most misunderstood character in the whole movie. Teddy Daniels sees Cawley as the master conspirator who's using Ashecliffe to carry out illegal lobotomies on patients in an effort to create a new method of mind control. But in reality, Cawley is simply trying to help Daniels understand his own delusions by letting him play out his fantasies in a safe manner. 

At the start of the movie, we listen to Cawley explain his dislike of modern medicine's habit of giving pills to patients or lobotomizing them, as opposed to using more natural means to cure them. And at first, this lecture feels hypocritical and even sinister, especially once Daniels discovers Cawley uses the lighthouse to carry out experiments on his patients. But then during the climax, when Daniels realizes the truth of his own delusions, it becomes clear that Cawley was completely sincere about his remarks at the start of the movie, so much so that he was willing to try the risky process of letting Daniels run around the island on his own in an effort to cure him, so Daniels/Andrew wouldn't have to undergo a lobotomy.

Filmmakers often make use of motifs in their movies to symbolize certain themes. In "Shutter Island," two things that Martin Scorsese keeps showing throughout the movie are fire and water, with both representing aspects of Teddy/Andrew's journey — denial and acceptance.

Fire represents a denial of Daniels' true identity, and that's why it's always prominently visible whenever he's suffering from a delusion. He sees flames in his dreams, as he believes a fire killed his wife, even though that's a lie. He sits by a fire in the cave when he talks to the other imaginary "Rachel" (Patricia Clarkson). When Daniels blows up a car, he imagines seeing his wife and daughter just as a large plume of fire rises in the air.

On the other hand, water represents Daniels' journey towards accepting the truth about himself. At the start, we learn that a large sea storm is keeping Daniels on the island, allowing him to continue on his path of self-discovery. We see water dripping everywhere as Daniels goes deeper down the path of his "investigation" and begins to accept the truth. And finally, when Daniels has to enter the lighthouse to gain complete enlightenment about his situation, he imagines doing so by literally swimming across the sea and climbing to the top of the lighthouse.