This saying repeatedly comes to Cady as she struggles to understand why she’s lost her memory. Whenever things get tough, this saying pops into her head and allows her to get through the situation. It’s later revealed that Cady was an actress before her kidnapping and memory loss, and that this saying is from her theater mentor. It’s a motif that arises when she needs to bolster inner strength, and symbolic of her past life, as well as her ability to take control of the situation by being calm.

Cady’s fingernails are ripped off one of her hands when she is tortured in the cabin. Even though she doesn’t remember the torture itself, the lost fingernails are symbolic of her memory loss. Just as she needs to nurture the wounds where her fingernails once were and where they will grow back in time, she must nurture her sanity and her mind until the fugue amnesia she’s dealing with abates and her memories come back; in other words, until her memories “grow back.”

The hantavirus that Cady’s parents discover and then find a vaccine for is symbolic of how humankind abuses nature. The virus arose naturally from mice droppings, and the Scotts made a vaccine.