The author forgot to draw an explosion at the top of the pyramid.
And yeah, Nezu actually is a bitch to use that scheme: First she suddenly asks Oogami if she and Yaginuma are dating because they look like a couple, but when getting a negative answer under that pressure (despite thinking they looked like a couple), she lets Oogami to understand she shouldn't later turn into a liar by showing interest in the dude, after all. If that's not a bitch move, I don't know what is.