How does Jodi Picoult use imagery in My Sister's Keeper?

Imagery:

"'I couldn't save her.' The words are ripped from his center. He hunches his shoulders, sliding backward into the body of a boy. 'Who. . .who did you tell?' He is asking, I realize, whether the police will be coming after him. Whether I have spoken to Sara about this. He is asking to be punished."'