In Bruges
Bruges is the setting of the film for the characters to exist in. It is also a symbol of purgatory, as Ray and Ken await judgement for what Ray has done in killing a child.
Principles
Harry is a man who believes that one must live by principles and without them there is no order, only chaos. Thus, when Harry kills himself, it is a symbol that he is a man who can no longer have principles and not live by them.
Redemption
Ken is ordered to kill Ray, and when he approaches him he finds that Ray is attempting suicide. Ken stops him and though he was there to kill him, now he encourages him that he is a good person. This is a symbol of redemption.
Ken's Jump
Ken jumps from the tower in Bruges knowing that he will be killed in order to warn Ray. His sacrifice is a symbol of his belief in the principles of redemption. So much so that he, like Harry, is willing to die for it.
Floating
We see Ray at the end of the film on a stretcher being carried to an ambulance. It appears he's floating away, and this is a symbol that we don't know where Ray is. Is he alive, dead? We don't know and by his use of language it doesn't appear that he's certain either.
