Quote 13
I must have had my face in the water and then hit my head on one of these rocks.
Like I said, I don't know.
I remember only this: I plunged down into this ocean,
down to rocky rocky bottom, and
I could see the base of Beechwood Island and
my arms and legs felt numb but my fingers were cold. (12.8-13)
Can you really see the base of an island? Can you sink to the bottom of the ocean? Does Cadence really remember these things?
Quote 14
In Europe […] I lay prone on the bathroom floors of several museums, feeling the cold tile underneath my cheek as my brain liquefied and seeped out my ear, bubbling. Migraines left my blood spreading across unfamiliar hotel sheets, dripping on the floors, oozing into carpets, soaking through leftover croissants and Italian lace cookies. (14.11)
Cadence's description of her headaches, like her other metaphors, involves her body melting into her surroundings. Not to be gross, but the other Liars' bodies quite literally melt into their surroundings when they die.
Quote 15
I made her tell me one last time, and I wrote down her answers so I could look back at them when I wanted to. That's why I can tell you about the night-swimming accident, the rocks, the hypothermia, respiratory difficulty, and the unconfirmed traumatic brain injury. (18.29)
Cadence claims she only remembers the accident due to what her mother told her, but in Chapter 12 she relates seeing the base of the island and feeling the numbness in her body. There's a whole lot of lying—or misremembering—going on here.