why did that happened to the mirrors

Will shrieks himself awake and Mr. Dark sends everyone home. Meanwhile Will and Charles run into the Maze to rescue Jim. Charles sees his reflections in the Maze, one million "sick-mouthed, frost-haired, white-tine-bearded men." He is momentarily overwhelmed with despair, but Will strikes a match and cries, "I love you," at which Charles confronts the images and lets out a tremendous laugh. The mirrors shatter.