So it looks like the far window on the bottom left of the map would be the easiest to lead/shoo out the wind spirit without being in sight of the counter.
If we can, open that window. (As I said before, the back alley labeled "concrete" doesn't feel attractive enough.) If it's a nice day maybe even ask one of the librarians to do it, so it's all official-like.
After that, it's experiment time. Waving the hand fan about might look a bit odd but seems least likely to cause a complaint. If we wave it at the geist, does it try to follow where we point the breeze or does it try to blow wind back against us? In the first case we can try to lead it out the window by pointing our breeze in that direction; in the latter case we would have to point away from the window and back up (I see this ending with us throwing the fan out the window for it to chase). Both ways I like the idea of leaving the pinwheel outside in the space marked garden as extra enticement to go out the window. Try to hug the far left wall, away from the librarians.
As far as Plan B stuff we can try (quietly) leaving a line of rocks down the middle left aisle, right along the ends of the shelves and also put some rocks atop the shelf ends, to encourage the geist to keep to the far left. I don't know if we can pull it off surreptitiously, however. Depends on how many other people are about.
Lets see if we can get it to follow us using just the pinwheel, if that doesn't work do one of the other things.
You know what, if it does want to follow / play with the pinwheel, that's probably easier than the whole thing I cooked up. We could either lead it to the window and try the "fetch" thing, or even walk it right out the front door. People might give us a glance or two but we'd be leaving anyway.