I think Paul is impractical in being attracted to the world of romance. When he is an usher in the Carnegie Hall, before starting the job he will go to the picture gallery and observe the pictures neatly, then he may ¡§lose himself¡¨ before the pictures. Later, he also feels exciting when the symphony begins. But the author points out that ¡§it was not that symphonies, as much, meant anything in particular to Paul¡¨ ,and what means something to Paul may be his own ideal and dream. Paul doesn¡¦t like the ¡§ugly¡¨ daily life so he tries his best to get rid of it as much as possible, and at the same time, tries to find something ¡§really¡¨ high-class and romantic. He may know nothing about music or performance, but he likes to enjoy them or to be surrounded by them so he can feel that he is in a wonderful world and has a zest of life. In short, Paul just has an impractical dream---to be in a romantic world, and he wants to make it come true.
As to Paul¡¦s ¡§elastic power of claiming the moment, mounting with it, and finding it all sufficient¡¨ my opinion is that it shows how deep Paul sinks in the music and cares nothing but his own happiness. He doesn¡¦t think more and just want to enjoy this kind of feeling.
At the end, Paul¡¦s father comes to New York to look for Paul. Paul feels that ¡§all the world has become Cordelia street¡¨ because he sees that his father is in New York as on the Cordelia street. At that moment, he learns that wherever he goes, his father will never leave him alone. Therefore, he knows there is no way out.
I think the flowers means Paul¡¦s dream. The color ¡§red¡¨ shows how much Paul desires to achieve his dream. Beside, the few red carnations and the whole white snow have a very evident contrast. I think this makes flowers/Paul unique from their/his surroundings.