The image on the tapestry Nicholas discovers in the lumber room becomes a symbol for the story's conflict between wildness and propriety, suggesting that Nicholas's wildness will triumph over the aunt's attempts to subdue him.
Had to look for the details and here is my answer.
"Saboteur" is actually a short story that was written by Ha Jin. And based on this story, the quote that best foreshadows the method of revenge by Mr. Chiu is this one: "I shall report you to the Provincial Administration. You'll have to pay for this! You are worse than the Japanese military police." Hope this answer helps.
