What specific moment is the climax of "The Sniper" by Liam O'Flaherty?

The climax is the highest point of interest in the plot of a piece of literature. In Liam O'Flaherty's "The Sniper," the plot revolves around the actions of a Republican sniper on a Dublin rooftop during the Irish Civil War. After revealing himself to the enemy by killing an old woman and armored car commander in the street below, the sniper is confronted with an enemy sniper who is out to kill him. The climax of the story comes when the Republican sniper kills his opponent after tricking him by pretending to be dead and dropping his rifle into the street. When his adversary comes into the open, the Republican sniper shoots him with his pistol. Everything after this point in the story must be considered the falling action and resolution, in which the sniper discovers the man he killed was his brother.