The speaker is lying inside an MRI machine, and the poem turns the experience into a nightmare of being buried alive. The scanner is a coffin, a tulip bulb in the ground, a cork pushed into a bottle. The noise overhead sounds like the world ending, and the speaker fights to stay calm, knowing that panic would only use up the little air they have. One hand rests on the panic button the whole time. We learn the reason for the scan: deafness in the left ear, and doctors checking for a brain tumor.
The mood shifts near the end. The speaker says they have adapted and feels thankful for small things like hearing at all, walking, making breakfast and friends. The humor in "make whoopie" lightens the tone. The final image, hearing Beatles records in mono and feeling like "the fool on the hill," is wistful but calm. Life is shortening, perhaps, yet the world keeps spinning, and the speaker is still here.