It's one of those things you don't really think about unless it's pointed out to you.
In another one of my favorite movies, The Fifth Element, the main "good guy" is Bruce Willis and the main "bad guy" is Gary Oldman, and Willis actually works for Oldman at the start of the movie (but gets fired), yet they never actually meet, never even share a scene. The closest they come is when Willis steps into an elevator a second before Oldman steps out of the one right next to it on the same floor.