The poem describes an empty, untidy room as if it were a film scene: a tracking shot down a dark corridor, a pan across the floor, a jazz tune, a yellow lamp. But the real subject is the mind of someone sitting there. Their thoughts keep trying to escape into the past, to sort out what the speaker calls the "indigestible waste" of a life gone by, and keep falling back to the room. The comparison with waves, which return again and again to the shore, captures that pointless repetition, and the speaker even finds the image a little tedious and "magnificent" at once.
The mood is cold, lonely, and weary. The winter wind, the black window, and a drunkard's unsteady steps on the stairs add to the bleakness. The refrain "There's no one in this room" suggests that the person is either absent or emptied out, an "invisible hero" watching themselves. The ending, "If only...", trails off unfinished, and the camera closes its "eyelid of shadows," leaving regret and darkness.