Final answer:
Santiago's facial expression emphasizes his innocence and confusion regarding the twins' motive to kill him.
Step-by-step explanation:
In the given context, Santiago's facial expression emphasizes his innocence and confusion regarding why the twins were trying to kill him. Facial expressions can convey emotions and thoughts that words may fail to express. In this case, Santiago's facial expression underscores his surprise and lack of understanding towards the violent intentions of the twins.