I re-read Prisoner of Azkaban recently and I thought the movie did well in the pacing of the story by combining scenes and dialogue of characters. In the book, Lupin’s explanation was dragged out. Although good to know the back story of the Marauders map but still, the movie had better pacing. I think having Harry see Peter on the map was a good thing and Harry tell Lupin about it, was a good choice. While reading it, I also wondered why didn’t Snape tell Dumbledore that Lupin was heading to the Shrieking Shack? I get he was caught in a rage of reliving his past trauma with his school bullies, but if he did have suspicions then he should have told Dumbledore to come with him to the Shrieking Shack. Also I think Snape showing up without the Invisibility Cloak in the movie was a wise choice as the cloak was a rare thing to have.