I think that Nishi made that to get more soldiers to Gantz, maybe he think that geting more people to Gantz will make the katastrophe easier, he killed the classmates do get the cops there and killed the cops to get elite soldiers for Gantz.
I think that Nishi's classmates will be in Gantz room...
Well... nishi probably didn't use the controler because he would have his brain fucked.
What do u guys think kurono will say to nishi?