"Shattering fast / I'm Glass / I'm Glass"

Towards the end of Franny and Zooey, Zooey Glass is talking to his sister on the phone and he tells her she looks "shattered." What is this if not an easter egg? You read this, you either pick up on the joke or you don't. If you do what've you got except a broken toy?

Do you kill a thing when you outsmart it?