"He found a big leather chair in the lobby, facing a window, and he put the overshoes and the puppy biscuit on the floor beside it."
As he waits for his wife to meet him in the hotel, Mitty ensconces himself in a chair, which is the first place in the whole story where he seems completely at ease with himself and completely free to indulge in his imagination. As we learn later on from his wife's arrival, Mitty was more or less hidden from the rest of the world in the big chair, which serves a kind of visual metaphor for his state of mind.
"War thundered and whined around the dugout and battered at the door. There was a rending of wood and splinters flew through the room."
In Mitty's World War I fantasy Thurber gives us a very rich description of the scene in the dugout under artillery bombardment. We get both overwhelming sound, depicted vividly through comparison to the natural phenomenon of thunder, and the kinetic force of materials exploding due to shell bursts.
"It began to rain, rain with sleet in it. He stood up against the wall of the drugstore, smoking. . . . He put his shoulders back and his heels together."
Mitty's final fantasy is just as vivid as the others but unlike the others is constructed from the same space and time as the reality in which Mitty dreams. Instead of switching to the imagery or scenery of another reality, Mitty finds dramatic potential in the miserable weather and incorporates it into a waking dream.
"Then, with that faint, fleeting smile playing about his lips, he faced the firing squad; erect and motionless, proud and disdainful, Walter Mitty the Undefeated, inscrutable to the last."
In the final image of the story, we get the first movie-like close-up of Mitty's face, encapsulating all the masculine virtues and charms that he has conjured up for himself through the different fantasies. All the adjectives are as though contained within that one expression: the smile.
