@Tamerlane I think it was a reaction to her hearing Reiji make a deal with Esomori on her behalf in the last chapter. She didn't ask him to do that either, so she's just trying to assert some control.
You know, what this manga really is all about is control. Reiji has the least of it, too.
I need to know how Gen and Reiji’s father fit into this mess.
I would actually love it Gen unironically has the hots for Reiji too, especially if he comes out as a yander psycho like the sensei.