The rumble is a warning to the others to leave the area in which the punishment is being carried out. The narrator feels that the rumble is similar to the one he experienced when he saw the god at the underground river. He feels that he is the one who created the world and that his existence does not make sense. The rumble reminds him of the last time he used the lightning to deflect the punishment of the god. He wonders if he is going to use the same lightning again.