After the exchange between Eiko and Enami-sensei, sensei goes her way annoyed that after being told off she ended without any candy... After being sure nobody is near her, Eiko nonchalantly reveals she still had another piece of candy...
While she's enjoying her yuri cloud 9, the scene shifts to a opposite corridor where Tamate watched everything but in a effort to not be found out stopped her retort about Eiko negating a new Candy to sensei just for the sake of the flirt and funny...
And in this exact moment she perceives that yet a fourth person watched everything, even her... and this one should be Tsubakimori Shachi, that for the little screen time she had is identified like some Eiko professional fan girl... The joke ends as she disappears like she was never there in the first place... much to Tamate's astonishment