The speaker of this short poem feels fragile and is trying to find the strength to protect themselves. The opening images, misheard voices, falling walls and slammed doors, suggest a home or inner world where conflict is close by and privacy is shaky. The speaker is shut out or shut in, and the walls offer little safety.
The attic scene is quiet, but it isn't comforting. A gentle breeze through open windows becomes a reminder of brokenness, because even something that slight can make the speaker stumble. That's the heart of the poem: a person who feels too weak for even small troubles, let alone bigger ones.
The ending turns toward hope. When the "hits" start raining down, the speaker wants to be able to defend themselves one day. The mood is sad and vulnerable, but the final wish keeps it from being hopeless. The subtitle, "Self defense," suggests that this hope for strength is the real point.