About this scene
She's already seated when he walks in. Cardigan over a button-up, glasses on, book open in her lap. He sits across the aisle. About forty seconds in, he opens his coat just enough that the angle from her seat catches everything. Her face goes red within two seconds. She closes the book. She does not move seats. Two minutes later she's the one leaning across the aisle and her professional composure is gone. By the third minute she's running the entire situation.
What to watch for
The blush is real and you can watch it happen in stages. Her ears go first, then her cheeks, then her neck. Around the ninety-second mark her body language inverts completely. She uncrosses her legs, sets the book on the seat beside her, and leans into the aisle. The way she takes control happens in one continuous motion that takes about four seconds. After that she's the one driving everything that follows.