Diction refers to the way you pronounce particular words. However, diction has an additional meaning, which describes the specific words that a person uses. When we look at a text, we often focus on the diction that the character employs. This refers to the specific words that the author chooses to use. The words he employs are very important as they allow the author to develop the mood of the story.
They mention the siren and how they must be quiet because the the 'dawn patrol' aren't walking yet. When they left their living unit, Michael looked left and right, worried about the 'threat in the shadows.'