At this part in the story we have almost no backstory of the character. She barely talks and we don’t even know her name. She’s going back to how she ended up here and talking about her family specifically her mother. She says
my mother was like a crab: she tucked every thing inside and left only her shell. (pg.28)
I know a lot of people deal with emotions differently and this quote specifically stuck out to me because showing your emotions can be a very vulnerable thing. Being open and honest about your trauma in your past makes you very vulnerable to another person. So I think it’s sometimes seems easier to “tuck things inside”. I believe that she is just describing small part of who her mother was, but it helps you understand the character a lot better. And how the way she coped with things shaped her as a person.