You don’t actually have to tell us that he’s been watching her for a while (like the first paragraph of this section does), because he tells her himself right here. 

I’m not saying you should delete all the preceding descriptions. No, no, no. I’m just trying to show a different way of looking at the structure of what you have going on here. 

I’m not exactly sure what the best way to do it is, but maybe start the following section with something that grabs the reader. 

Maybe...start with the creepy dialogue down below (the "Mary Ann...Mary Ann" part). THAT part is super interesting. Maybe start with that and then kind of backward-engineer the descriptions you build in the paragraphs that precede it.