The dramatic climax of the story occurs when Jerry reaches the end of the tunnel and makes his way to the surface. Doris Lessing creates tremendous suspense prior to the story's climax. After Jerry enters the tunnel, it is questionable whether he will make it out or die in the effort. Once, he thinks he has reached the end only to discover it is not the end of the tunnel. The physical toll on him increases until he lapses in and out of consciousness. He struggles on, surrounded by darkness, believing that he is going to die. Because of this development of suspense, the climax of the story is very dramatic:
An immense, swelling pain filled his head, and then the darkness cracked with an explosion of green light. His hands, groping forward, met nothing; and his feet, kicking back, propelled him out into the open sea.
The climax of a story is reached when the main conflict is resolved. In this story, Jerry challenges the tunnel and himself. He wins--and lives.