Final answer:
Sierra may not share about the murals due to personal emotional conflict or to protect something valuable, fearing misunderstanding or harm.
Step-by-step explanation:
Sierra may choose not to tell her family about the murals for several reasons. First, she might be experiencing personal struggles or emotional conflicts that she feels they wouldn't understand or that would burden them. Passages suggest she is dealing with heavy, internalized issues such as 'dreams of dead bodies' and 'fires burning in the desert.' Second, her silence could be linked to protecting something valuable, akin to the character Sylvia, who cannot speak of the heron for fear of betraying a cherished secret. Sierra's reluctance to share may stem from a desire to keep something precious intact, away from outside influence or harm.