A puzzling part of the film?

So it is implied Elsa was working for Szell the whole time.

Then I guess that means she was instructed to infiltrate Babe's life. But why did she play so 'hard to get' at the library and back at her apartment? It seemed she was relying on causing Babe to fall for her at first site and then pursue her back to her apartment over a lost book, and then she continues to tell him to leave at least 5 times? Wouldn't it have been a bit more simple to act more eager. I don't understand why she had to even infiltrate Babe's life, and also... why were they mugged by Szell's assistants in the park!??

I guess I'm just really confused at exactly what part Elsa plays in this movie?

And also... What was the soccer ball all about?!!

And who was the asian man trying to kill Doc working for?

Too much of this film went straight over my head.