Within the riotous, if not scandalous, atmosphere of the apartment that Tom has rented for Myrtle and in which Nick finds himself within an assortment of odd afternoon partyers in Chapter 2, Nick feels detached from (yet, as always, acutely observant of) what is unfolding around him. His narrative stance allows him to conclude, based on his own description, that what is going on in the apartment—the seemingly meaninglessness exchanges and general frivolity—is possibly going on unnoticed in countless apartments around the city. He feels that he is "within and without, simultaneously enchanted and repelled by the inexhaustible variety of life."
It is worth noting that Nick feels this way about almost all that he observes throughout the novel. Of further interest is that Nick can see himself in the scene. Referring to the "casual observer" in the street beneath the apartment, he thinks, "I was with him, too, looking up and wondering." This constitutes a significant formal apparatus employed by Fitzgerald in "The Great Gatsby": as an internal narrator, Nick is able to be both a character in the story, swept up in the tumult of Gatsby and Daisy's world, and the detached observer, appalled by human affairs.