How does the author use foreshadowing in Parrot and Olivier in America?

In Section Six, Mr. Eckerd and Miss Desclee talk about a play in which Miss Desclee will play both parts. This foreshadows the play Parrot will later attend in America, and when they disappear to work on it, Parrot rushes his enemy, throwing the portrait of Olivier into the sea and making himself a public madman so that Olivier is permitted to lock the door against his servant while sitting for his portrait.