What Does The Ending Of Shutter Island Really Mean?

Ending Theory #3: Andrew Chooses To Be Lobotomised

It may be that Andrew Laeddis knows exactly what he's doing in the closing scenes when he begins that long walk towards the lighthouse. Many have taken his last line - given to the closest person he has to a confidant, Dr. Sheehan - as a final indicator of his self-awareness: "Which would be worse? To live as a monster, or to die as a good man?" This could just be the ramblings of a man that for two years has been constantly on edge, but the line's placement at the very end of the film would suggest otherwise. The implication is that Andrew sees 'dying' - or in this case being lobotomised, a procedure which will in effect kill both the old Andrew and 'Teddy Daniels' off for good - as the preferable alternative to living as himself any longer. After all the horrors the film has displayed by this point, it'll be understandable to some viewers. Teddy has killed in cold blood, lived through an unjust war, alienated close ones with his drinking, lost all three of his children and murdered his own wife, leaving him suffering from a level of trauma that anybody would find it difficult to live with. That Andrew at the end of Shutter Island chooses his fate is the most obvious interpretation of the film's ending. Why he does so, however, could be interpreted one of two ways: either Andrew can no longer bear the guilt, or he's aware of the damage he can cause, and has decided it's time to remove his violent, volatile self from society.