Trivia: When Teddy enters the lighthouse, as soon as he begins to climb the spiral stairs, the camera follows his movement from in front of him. However, as Teddy and the camera wind around the stairs, the wall behind also appears to move with them, as though what is REALLY moving is only the staircase itself, rotating on its central axis. Yet another point (added to the various disappearing glasses/bottles) that adds to the general 'insane' feel of the film.
Trivia: During the ferry approach at the start, we are shown Shutter Island. In actuality this is a combination of Peddocks Island (the decaying brick buildings), Maine's Acadia National Park, Massachusetts' Medfield State Hospital, and Turner Hill Country Club's Rice Estate (located in Ipswich, MA), which were combined via CGI. Additionally, the mountainous region of the island (shown as the ferry approaches) was also CGI, and added in post-production.
Trivia: The scene where all the soldiers are shot along the fence is historically accurate, though there is debate on the exact numbers.
Chosen answer: I think the recurring blood comes from the blood of his wife when he killed her. there was a lot of blood you see, in his psychosis that means a lot and has taken over a large part of his hallucinations, just like Dachau camp. Yes, he did shoot his wife Dolores, in the belly. You can see it in the end of the movie.
lionhead