The audience is meant to sympathize with Gus, the well-meaning, slightly slower junior partner-in-crime to Ben. We are in the same position as Gus: like Gus, we are not familiar with the job they are going to perform, we don't know what exactly is happening upstairs from the basement, and Ben's betrayal should be as much of a shock to us as it is to Gus. Gus is somewhat child-like, pestering Ben with numerous requests, complaints about their environment, and questions. He is generally submissive to Ben's orders—everything from making tea to investigating outside the door—though he stands up for what he believes in, as with the "Light the kettle" argument.
Gus is more sensitive than Ben to issues of traditional human concern. He often touches upon deeper issues Ben does not wish to contemplate—about death, the dull routine of life, and the nature of the elusive employer Wilson. He is concerned with the consequences of his job. He is haunted by the image of their messy murder of their last victim, a girl, and is anxious about this next job. He is fed up with the dull routine of life, but can do nothing to get out of it. His recurring trips to the bathroom underscore his imprisonment to routine, especially in contrast with Ben, who never goes to the bathroom. Unlike Ben, he has no hobbies, which accounts for his awareness of his static life.
If one were to read The Dumb Waiter as an allegory of capitalist slavery, then Gus is the employee who, because life offers him so little, recognizes something wrong with the class structure. He sees cracks in the façade of Wilson—he is unafraid to yell and peer up the serving hatch to where the god-like figure reposes—but still feels uneasy in his presence, as most underlings do with their powerful bosses. He also places accountability on Wilson as the controller of the means of production; although Ben tells him otherwise, Gus believes that Wilson owns the café and should therefore pay for the gas meter (he is also miffed that Wilson, or the person upstairs, wants tea while they are hungry and thirsty). Gus's class-consciousness includes some shame about his poverty, but it is less than that exhibited by Ben. When they send their working-class food up the dumb waiter, Gus calls out the brand names as if announcing a fancy dinner menu. Many productions of The Dumb Waiter will give the actor playing Gus a Cockney accent to emphasize his lower-class standing, but little else is known about his background. We learn that he has not seen his mother in a long time, that he enjoys soccer, and is somewhat unfamiliar with the richer sport of cricket.
By the end of play, Gus becomes somewhat resigned to his life enslaved to routine. He accepts Ben's instructions to kill by mechanically repeating them. When he realizes that Ben is betraying him, his silence does not seem like one of shock. Rather, he has turned into a dumb waiter—manipulated by others to carry out their directions, unable to speak for himself.