Haha, for a such a long-standing relationship Miho sure is ruthless in throwing it all down and drawing the line! Though I think it's more like "getting into a fight" than "getting dumped" - overreacting much Mashiro? Well I guess for him he would be inexperienced with this subject.
Miho on the other hand, is either very angry, very clever, or maybe a mix of both. It'll definitely force Mashiro to significantly act to solve this Shujin problem, which is how I saw it.
In any case, this chapter did open up things quite a bit. Wondering how all the new mangas will do, especially Aoki's and how it'll effect this whole Shujin love-polygon thing; with another reason as it's basically her rip-off of M+M's love story rofl. My guts want to hate Nakai, but remembering how he was dumped -- made me kind of understand why he's probably acting that way. Doesn't mean he's not a jerk of course. And then, thanks to Freeter, I was reminded of Eiji's "cancellation" card in his pocket, which really made me reread his comments towards the new series'...