The speaker keeps undercutting their own drama. The refrain "It was barely a whistle" shifts to "It was barely a trip," as if each big moment is being shrunk the second it's described. Banging on a barn door sounds desperate, yet the brackets insist it was hardly a sound. The speaker even admits that "melodramatic is my default position," so the poem seems to know it exaggerates, and keeps correcting itself.
Something still happens: someone hears the call, and the speaker takes a "guided fall" that turns into a pleasant tour. Judging by the tone, there's relief and a little gratitude, maybe toward whoever answered. The ending, "rain-soaked sandwiches," is a funny, deflating image, small and soggy after all that fuss. The mood is wry, shy and lightly comic, with real feeling tucked behind the jokes. The speaker seems to be playing things down because admitting how much it mattered would feel like too much.