Memories simile
"Unlike Cate’s memories, which came and went like fluttering eyelashes, Rob’s thoughts seemed almost lethargic…velvety and murky. They didn’t piece themselves together so much as seep into one another—like ink dropped into a glass of water, the dark mass stretching and slithering until it finally polluted everything that had once been clean."
Ruby is able to get into people's heads and see their memories. She has seen Cate's memories before and was unable to find anything suspicious, but when she sees the memory of her partner it is then that she realizes the intentions of the Children's League.
Grave of past lives simile
"Several of the larger, more permanent trailers had entire walls ripped or charred away, revealing kitchens and living rooms with their insides still intact, if not waterlogged and infested with animals and slowly rotting leaves from the nearby trees. It was like a mass grave of past lives."
This comparison strengthens the post-apocalyptic theme that the entire outside world is made out of. Abandoned and rotting homes paint a lifeless picture.
Screen to the outside world simile
"The heat from a hundred-odd bodies fogged the bus windows, and it acted like a screen to the outside world."
This quote is from the beginning of the novel when the children are taken to camps. It foreshadows that these kids probably won't leave these camps to see the outside world ever again, not alive at least.
Monster metaphor
Ruby thinks of herself as a monster because of her abilities. She believes that the PSFs aren't the real monsters in comparison to her. If we compare this to what we learn from how the PSF's treat the kids with abilities the idea that we get is opposite to hers. Her opinion is rooted in the beginning stages of her power discovery when she made her parents afraid of her.
