Apparently, Mrs. Vinyl was not scared to death from the airplane antics, because we learn that she had eaten one of Jack's mother's casseroles the following day (um, wait....are you getting a bad feeling about this one?).
Mr. Huffer is already on the scene at Mrs. Vinyl's house when Jack and Miss Volker show up.
Miss Volker jokes that Mr. Spizz probably "helped her kick the bucket" (23.20), and then they note that it looks like Mrs. Vinyl died while "having a midnight snack" (23.21).
In the refrigerator is—you guessed it!—another one of Jack's mother's mushroom-and-cheese casseroles.
Jack almost (no, Jack, don't!) eats a slice of the casserole, but is interrupted by Miss Volker.
Mr. Huffer and Miss Volker have some heated philosophical words regarding the impending demise of Norvelt, death, and history.
Norvelt should be used as something more than a "museum piece," Mr. Huffer argues—like taken apart to build a new town. Miss Volker, though, wants it to be "a shining city on a hill" (23.25).
"Nothing lasts forever," Mr. Huffer tells her, and she counters this with: "History lasts forever [...] And we'll be judged by our history" (23.79).
We discover that Mrs. Vinyl has died on August 6, the same day as the bombing of Hiroshima (the first-ever use of a nuclear weapon). Miss Volker launches into an impassioned diatribe on the inhumanity of war (23.37), and Jack has a moment of major insight about learning from one's mistakes (23.46).
After the reminder about Hiroshima, Jack's Dad decides to build a bomb shelter for reals.