I've included a link to the full text of the novel below. If you click on it and then scroll to the bottom of page 81, you will see that the last paragraph on the page begins with the line, "Sethe knew that the circle she was making around the room, him, the subject, would remain one." She is trying to explain to Paul D why she killed her daughter some eighteen years before, after Stamp Paid showed Paul D a newspaper clipping about Sethe's murder conviction. However, she knows that she will never be able to explain it to someone who does not already understand. Sethe describes to Paul how "She just flew. Collected every bit of life she had made, all the parts of her that were precious and fine and beautiful, and carried, pushed, dragged them through the veil, out, away, over there where no one could hurt them." Sethe claims that killing her children would make them safe because they could not be returned to slavery if they are dead. She feels that she was doing the only loving, appropriate thing by keeping them away from the slave catcher and schoolteacher. Death was safe; slavery was not.