And Lancelot knelt down and took the king’s beloved hand in both of his and kissed it. “Good night, my liege lord, my liege friend,” he said, and then stumbled blindly from the room and felt his way down the curving stone steps past the arrow slits.
As he came to the level of the next landing, Guinevere issued silently from a darkened entrance. He could see her in the thin light from the arrow slit. She took his arm and led him to her dark chamber and closed the oaken door.
“A strange thing happened,” she said softly.
Source: Steinbeck, John. The Acts of King Arthur and His Noble Knights. New York: Penguin, 2009. Google Books. Web. 7 July 2011.

What is the author’s purpose in the above passage, and how does he achieve it through his organization and choice of details?