In "The Walls," the speaker treats the walls around them as a silent companion, the one thing that has seen everything. The walls have held the lies, the tears, and the voices saying "no" and "you can't." The speaker wishes they could speak, because, as they say, only the walls truly know them. That suggests a lonely life where no person has really been let in.
Over the four stanzas, the walls shed, then melt, then vanish. It reads as if the speaker's one steady witness gives way under the weight of their pain, which includes sleepless nights and exhausted days. By the end, the speaker even doubts the walls were ever there, and imagines they left because the speaker was "too far gone." The mood is heavy, tired, and isolated. The ending is especially sad because the speaker blames themselves, as if even something that cannot move or feel has given up on them.