Writing With Subtext

A key thing here. Noticed this in my tearing down of Casablanca. It’s weird but Rick’s throughline (SP1) doesn’t kick in till the second act (by conventional standards of time; a good third of the entire film). What’s was even more intriguing is the mixing of the PSR variations in a non-sequential order: I’m guessing this might be an exposition- storytelling choice or something?
Quite interesting.