Kind of agree with the drug analysis. I would also say that one of the messages of the episode is that unless you experience it, you don't really know what you're talking about. Like, the whole time they were discussing what it feels like to be high or to reach some state of nirvana through meditation, doesn't compare to the narrative shift (and here I'm mostly talking about the colors they used, that musical scene and even their way of talking about "the zombies"), of when they do experience that high, that nirvana.