In the crypt, Madison's tattoos are red and irritated but when a prisoner, before being in the crypt, they're not.
When Madison is buried up to her neck on the beach, the sand flexes as she breathes. But if Dickens really were buried up to her neck, the sand would not flex, like it did, when she would breathe. Sand would compact on her and not flex making breathing difficult. Obviously, she was placed in a hole (and sand not placed in the hole with her) while a cloth was placed around her neck. Sand was then placed on top of the cloth (and that would flex as she breathed), giving the illusion that she was buried up to her neck.