I don't want to give things away, but we know Nick gets taken by the bad guys. I'm not sure what visually confirming that would do. Regardless, imo, the point of the movie isn't really to factually confirm those various issues, but how rattled Bill is from it all. If you read the article they place on the screen twice, it's filled with these double words and sentences, all clearly referential to elements of the film. I used to think it was Kubrick "trying to tell us something" but these days I take them more as Bill's incoherent approach to the world around him as he's on day 3 of his bender, i.e. the words and phrases are doubled up because he can't see straight anymore, his dreams are blending into his life (just as his life blended into his dreams).

That prick piano player Nick Nightingale ended up making some interesting movies of his own.