The old woman introduced into the sniper's saga is representative of several ideas. She is described as old and wearing a tattered shawl. This paints the picture of a destitute woman hardened by the war. She points out the sniper's location to the man in the turret. The courage it takes to be an informer on the front lines of the war is another theme shown through the old woman.
The sniper ultimately shoots and kills the old woman for the perceived betrayal. Her lifeless body is referenced later as laying in the gutter. This moves forward the theme of innocent deaths. She may have been a traitor to the sniper, but to the other side she was an innocent old woman. This reminds us there are two sides to every story.
The interaction moves the story forward because of the casual nature of her death. It is seen as a routine matter for the sniper, helping to define his character as cold and without empathy. The reader's relationship with the sniper is important due to the ending. The more the reader abhors him, the more impact the end will have with the reader, requiring the reader to question their own perceptions of the story.