Someone keeps pushing the speaker until their anger finally erupts, and the poem describes that eruption in violent, bodily terms: a roar, a heart "ripped from its veins." But the poem's real subject is what comes next. The speaker admits that without the anger they feel like "nothing," a tiny, insignificant person. The anger seems to be the only thing that makes them feel solid, and the breakdown that follows leaves them facing silence and loneliness, which they fear more than the other person's cruelty.
That fear explains the ending. The speaker knows the other person is "toxic and rude" and "utterly unworthy" of their time, yet they stay. The plain, short final line makes the choice feel heavy and a little defeated. The mood is raw and painful, mixing rage with shame and resignation. The broken, shrinking lines on the page, where "a tiny / insignificant / person" falls one word at a time, mirror how small the speaker feels. The title, "Cement Legs," suggests being stuck in place, unable to walk away.