The narrator says that he is a revolutionary rather than a murderer like Torres. Yet, he constantly refers to how easy it would be to kill Torres...

On the surface, there does appear to be a contradiction between the narrator's comments and his behavior. However, taken in light of his true goals as a revolutionary, we come to understand that the real conflict is caused by his warring emotions. In literary terms, this is a man-versus-self conflict situation.

Revolutionaries often pride themselves on their adherence to lofty values; whether they fight for freedom, independence, or the right to self-determinism, no self-respecting revolutionary wants to be known as a mere murderer. Perhaps this is a rather romanticized view of the motivation of revolutionaries; yet, the text does hint at this interpretation of affairs. Above all, revolutionaries like the narrator need to be pragmatic. If he exposes his true identity by committing a gratuitous act of murder, he will gain nothing but notoriety as a cowardly executioner and subsequently, an infamous death. He will have done nothing to forward the cause. Instead, he will have betrayed his own ideals to indulge his human thirst for vengeance.

No one deserves to have someone else make the sacrifice of becoming a murderer. What do you gain by it? Nothing...And what of all this? Murderer or hero? My destiny depends on the edge of this blade...But I don't want to be a murderer, no sir. You came to me for a shave. And I perform my work honorably. . . . I don't want blood on my hands. Just lather, that's all. You are an executioner and I am only a barber. Each person has his own place in the scheme of things. That's right. His own place.

So, while he trembles 'like a real murderer,' the narrator understands that he must not betray his own sense of justice if he wishes to fight with a clear conscience. He tries to reassure himself that he doesn't want to kill Torres, but he still emotes like a murderer who is about to do the deed; he becomes nervous and sweats profusely. This is the initial contradiction between the narrator's comments and his behavior; however, his final actions show that he has conquered the conflict within himself. He does not kill Torres and earns a surprising confession from the Captain before he leaves.