I think that one of the strongest tonal elements established in "Jet Song" is the idea that there is an evident division in how being in the world is constructed. One is a "Jet" or "the other."  There does not seem to be any other equivocation.  The idea of "When you're a Jet, you're a Jet all the way," reflects how consciousness is immediately established in division.  This is the tone that drives the story.  Division is everywhere in the narrative and brings about the tragic collision that results. Jets vs. Sharks, Bernardo vs. Tony, Officer Krupke vs. young people, The Jets vs. Anita, Doc vs. Jets, Maria vs. the world except for Tony by the end of the narrative are all examples of how division drives the characters in the musical.  The song brings this tone out in clearly defining consciousness as a divided state.  One must fall into line "from your first cigarette to your last dying day."  No alternative to this seems to be evident, as the chorus that resounds affirms the division "like a bat out of hell."  If one seeks to find an alternative to the song's tone of division and stratification, "someone don't feel so well."  This becomes a clear tone out of the song and one that drives the musical.