Yori may have barely reacted when Akira popped up behind them, but Kozue almost jumped out of his skin. "Don't do that!" He snapped, whipping around to glare at Akira. "Do you want me to have a heart attack? Is that what you want, Akira!?"
Shock and stress was serving to make him more talkative, even if that talk was mostly just babbling and grasping at straws as he tried to keep the situation under control. In fact, he should probably just give up on the whole "control" thing right now, going by the way that freshman girl had just shoved past them to root around for whatever probably cursed school supplies had been left behind here. He didn't even know where the rest of the underclassmen went, so they were probably long gone, in one way or another.
Kozue's morbid train of thought was briefly interrupted as Masato quite literally rolled up to look into the classroom with them, and then immediately resumed when Masato made a dumb comment. "No. No death yet, no death ever. Death is illegal, nobody's dying here. I'm not allowing it." He huffed.