Just coming here to look the comments' box... and laugh at early hours bc nobody seems to take a grasp on why Kazuya is behaving like this.
He's fucking cornered on this. Nagomi told him that only a boyfriend like him can do what must be done... thing is that... he is neither his bf nor his friend, just his neighbour and barely coworkers. On the situation he's being put into (all of this his fault, but whatever), i think he was wise enough to call Sumi (she helped him with the movie idea and hearing things from a girls' perspective, a friend of Chizuru no less, can give him a better understanding of the shit he's into), as he never had a gf, neither the experience to handle these situations. As he said, there's a fucking big-ass wall between him and Chizuru (metaphorically and physically speaking). And he doesn't know how to climb that wall, neither how to break it.
But it looks like us westerners can't understand japanese boys and their social cues. Specially unlucky and socially inept cherry boys like him. Thing is that he's taking responsibility for his actions, but doesn't know how to enact that responsibility.
PD: it seems Ruka will come back soon and stir shit up, making that wall taller, stronger and thicker. Miyajima leaked something on his twitter.
PD2: Sumi-chan, as cute as always. Her smile and motor clumsiness are the cure for my suffering, drama and nekketsu filled heart. Even when tripping over small things she looks cute.