How is this relevant to the story, you ask?
Firstly, how dare.
Secondly, all in due time.
Susan's hand might look odd, given that she's opening a mail box.
What's going on is there's a small hook to make the door easier to open, and Susan is using just her pinky finger to open it, minimizing how much she actually has to touch the mail box.
Not that I find that that's the sort of thing I would do. Of course not. I never, EVER use my pinky fingers to open things in an attempt to minimize contact with them. Not once.
Except for maybe several times a day.
(I also totally double or triple check things like this.)