The speaker watches a woman who seems lost in her own height. She "hovers above planet Earth," planning safe landings, yet she can't see that she is already on the ground, and that someone is watching her. The comparisons the speaker reaches for, a crazed cat, a maze-rat, a tied-up mime, make her seem trapped, frantic, or silenced, even while she imagines herself free.
The speaker's feeling is helplessness. "I cannot save someone so / high up or far down" admits that she is out of reach whichever way you look at it. The black thread about to snap adds dread, as if her state can only hold so much strain.
The ending is the most unsettling part. She reaches for champagne, a celebration, while the bubbles "lunge up to break." That image suggests joy that bursts as soon as it rises. The mood is tense, anxious, and tinged with sadness, with a bright surface covering something fragile.