Symbolism (source: litcharts.com)
The real-life Walter Mitty keeps his true self hidden, literally and figuratively. Whether he’s reluctantly putting on
gloves and
overshoes in obedience to Mrs. Mitty’s concern about his health, or planning to wear a
sling on his arm to save himself from embarrassment, he believes concealing himself is necessary for his own protection; revealing his true self in any way would mean a risk of
exposing his flaws. In his fantasies, however, Mitty is completely in control of what he conceals or reveals, and concealment is always an example of his strength. His heroic alter egos are calm and cool, expert at controlling their feelings—in particular, the enigmatic fighter pilot Captain Mitty remains self-possessed even while drinking.
But Mitty won’t accept any concealment imposed by others. In the courtroom fantasy,
he refuses to use the sling as a disguise even when it could potentially save him from conviction: he wants everyone to know the truth about him and his abilities. His declaration, “To hell with the handkerchief!” in the final scene is similar—in declining a handkerchief blindfold, not only does he refuse to show fear before the firing squad, but he also refuses to conceal his face.
For “Walter Mitty the Undefeated, inscrutable to the last,” this moment of pride and bravery is triumphant in spite of his death. Yet there’s a sad irony to the fact that he remains “inscrutable”—that is, impossible for others to understand—up to the moment of his death, because this description applies to his real life as well as his fantasy. Just as his wife appears to be a stranger at the beginning, he will always be unknown and unknowable to her, and nobody will ever know what goes on in his secret life.