Because Niishi was the only one who knew anything. Of the Tokyo team members, no one else knew anything at all about the grand scheme behind things. It was ultimately a good decision, because otherwise they would have been completely caught unaware by the invasion and Armageddon phase of things. Not knowing definitely would have changed the way they all acted in the final days, including Reika's decision.
Niishi seemed to have some kind of insight about the government knowing about the coming [giant] aliens, you definitely see the parallels now between the Gantz tech and the giant's tech. Even if he didn't know everything, he was a hell of a lot less in the dark.
Not just because of the body. She deserves a lot of credit just for listening to Kei that first night. She took that and other advice he gave and became a rather capable leader in her own right, rather than becoming a puddle of crying and whining goo like so many "participants" before her. Not to mention she never truly broke in the face of all this adversity.Outside of that, I was super happy to see that Reika got her Kei lovin. An Idol has to have her goodies, but with that body, she deserves it!
She's a sly one, but she definitely deserved something out of all this, even if Kei-clone wasn't too happy about it when she first told him.
I'd be really disappointed if she left the guy, and then Kei didn't rebuke her on the spot just because she's suddenly going after the only guy who could save her. If Gantz has shown us anything, those who do things out of cowardice and fear die quickly and very horribly.I also hope there is a nice exchange of words between that punk and his girlfriend that Kei had a crush on in middle school. I'd love to see Kei just verbally own that guy, and get his girl to leave him.