The film within a film

I guess we aren't really supposed to pay too much attention to the film that's being made during the course of this film, but I do have to mention it's kind of weird. In the early part of the film within the film, Esther Williams and Cyd Charisse appear to be two exotic native girls fighting over the handsome Navy Lieutenant. Then later, Cyd Charisse's character seems suddenly to have become a dancer in a nightclub, and Esther Williams' character a show-biz swimmer doing a water ballet. At the end of the ballet, we even see Cyd's character in contemporary Western dress. It's really kind of ood, but than I guess it's just not supposed to make any sense.