"Runaway"'s tone is pessimistic and tragic. At its beginning, the story clearly establishes the bleak circumstances Carla faces. Through the depressing turn of events, it unflinchingly relays the tragedy of Carla's life. The story maintains an honest attitude, accurately reflecting the unglamorous, complicated reality of human relationships. In describing Carla's initial attraction to Clark, Munro writes:
One day she came into the stable and saw him hanging up his saddle and realized she had fallen in love with him. Now she considered it was sex. It was probably just sex.
This passage is representative of the story's frank, honest tone. Looking back on her first encounter with Clark, Carla can likewise see the situation without rose-colored glasses, as not "love" but merely "sex." Carla at first romanticized life in the country with Clark, but now she faces the less glamorous reality. It is this darker, less glamorous version of events that the reader experiences. The tone does not disguise Carla's struggles in overly poetic language but rather conveys her grim circumstances in an undramatic, matter-of-fact manner.
The pessimistic attitude peaks at the story's end when Carla imagines Flora's "little dirty bones in the grass. The skull with perhaps some shreds of bloodied skin clinging to it." The phrases "little dirty bones" and "the skull" reflect the brutal reality of Flora's state without romanticization. Flora is no longer a majestic goat, but a defamiliarized set of bones and "bloodied skin." By ending on this graphic description, the narrator refuses to paint an optimistic picture or change to a more upbeat tone. Although Carla considers that Flora "might be free," the vividness of the description of her carcass lingers, and the story ends on a dark note.