You're writing a book and creating an outline which consists of beginning, middle and end. All you have to do is fill in the details. Right?

That may be precisely what Mueller is doing. He already has all the goods he needs but now he is filling in all the details to make sure there are no loopholes/mistakes,omissions. An airtight case that once presented will be unshakable/unbreakable/unmistably complete. That's what the donjohn and his spoineless toadies fear most. Mueller ALREADY KNOWS EVERYTHING AND HAS THE GOODS ON HIM. I can hardly wait for the denouement. SIGH.