Michael's Life on Half a Page
In the first chapter of this novel, Michael is describing the boringness of his life (pre-electric powers). He uses the illustration of a fifth-grade assignment: his teacher asked him to write down his whole life on one page, and he could only fill half of it. The image of this half-filled page symbolizes Michael's unremarkable life before the events of Book 1.
Michael's Face
Michael has Tourette's syndrome, which causes his face to tic uncontrollably, especially in times of stress. This facial imagery is a visual representation of any situation's level of stress; when his face is tic-free, he's finally relaxed, but when it's notably ticking, there's a high level of stress in the environment.
Electric Rats
The imagery of the electric rats is highly evocative of the nature of the Elgen as a whole. Their beloved power source is a bowl full of repulsive, cannibalistic, genetically modified vermin who are famous for extraordinary self-serving tendencies (hence the derogatory term "rat"). This image throws a particular interpretive light on the core of the Elgen: they're base in aim and lowly in pursuits, desiring power by means of "whatever works."
The Elgen's Uniforms
"They were wearing black rubberized jumpsuits with helmets, masks and gloves, which made them look more like machines than humans. Each of them carried a chrome weapon I'd never seen before" (Ch. 10).
When the Elgen invade the safehouse in Chapter 10, their appearance makes them look like machines rather than humans. This comparison is more than just an image; being completely without morality or consideration (key components of humanity), they are, in fact, more robotic in character than human. This sterile imagery reflects the sterility of their souls.
