Quicksand is the speaker's picture of a life lived on the brink of collapse. The feeling of danger never goes away: one wrong step, and they could go under. Yet the disaster they expect doesn't arrive on schedule. Two minutes pass, their head stays above ground, and they can't say why. Even good moments are short, since the sinking starts again almost immediately, first the feet, then the legs and stomach.
What makes the poem interesting is the rescuer. Someone, referred to as "she," keeps pulling the speaker out, and the speaker admits they've never stopped to wonder why. But being saved isn't the same as being safe. She lifts them out and leaves them in the same spot, so the cycle simply starts over.
The mood is tired and uneasy. The plain, repetitive language, and the way the opening lines return near the end, make the speaker seem trapped in a loop, grateful for help but still without a way out.