This is definitely a very good statement to explore when thinking about the character of the barber in this tense story. Certainly, as we discover, there is a lot more to this timid character than first meets the eye, and you will need to explore how the author presents the barber's involvement with the rebel movement through the barber's first person narrative. Of course, the barber at first is shown to be a nervous character. The mere presence of Captain Torres in his shop makes him tremble and he is only barely able to make casual conversation with Captain Torres whilst preparing to shave him. It is only when the barber refers to people of "our faction" that we understand that he is one of the rebel's that Captain Torres is determined to exterminate, that makes his position precarious.
However, you will need to consider how this statement can equally be applied to Captain Torres as well. His appearance does not reveal everything about his character, as we discover at the end of the story.