Is Gantz playing favorites
The general consensus has always been that Gantz doesn't give a crap about anyone and thats probably true...for the most part. But there has been some evidence that he...well, I don't want to say he cares about them...but that he may actually respect some of the team members and plays favorites.
For instance, he used to call Nishi "Mr. Nishi". Not "dumbass" or "numbnutz lolz" or "shortzy" or anything like that. He listened to what Nishi said (for the most part" and they seemed to have a good "relationship" given the circumstances.
Izumi. Gantz liked this guy so much that he actually made an effort to get him back after he chose freedom. Do you think it's a coincidence that his memories started coming back? Or that he was given that little black ball? Gantz probably transported it to his room at night some time after he chose freedom. And Gantz has never made fun of him during scoring.
And then theres Kurono. You could easily make the case that Gantz hated this guy. He made fun of him, threatened him and even had them kill his girlfriend. Yet through all of this Kurono thrived and became (arguably) the best Gantzer we've ever seen. He probably developed respect for him. The kind you would have for a worthy adversary or rival. The kind a bully would have for the nerd who punched him in the nose as retaliation for picking on him. Plus Gantz could respect him because, let's face it, he got the job done.
Which brings me to my real point The Osaka mission is probably the most dangerous mission the team has been on. It has 3 high level (60 and above) aliens including a 100 pointer. There are hundreds of aliens on it, some ridiculously weak and some decent. In terms of point potential it's even better than the Oni mission. So while being the most dangerous, it could also be the most rewarding.
The timing of this mission has me thinking (I know, thinking is bad). The fact that this "buffet" was laid out before them as the mission right after Nishi and katou were brought back and (more importantly) after Izumi and Kurono were killed makes me think that Gantz might have actually set up this mission so that Tokyo would be able to get stronger, either by reviving strong Ganters or by getting strong weapons.
The sheer number of points out there means that multiple members or Tokyo could get 100 points easily. Maybe even 100 points multiple times. The only issue would be the existence of Nuri and thats what the Osaka team is there for (yeah, yeah I know it's their city but work with me on this). For the most part (not counting Katou, Takeshi, Kaze and HS) Tokyo has done NOTHING and the Osakans have done just fine (except for the Nuri thing). If Oka ends up killing Nuri as most believe he will, then there was really no need for them to be there.
If thats the case then what really is team Tokyo's purpose here other than to try to rack up points. Maybe Gantz wanted to give them a mission where it was possible for them to get as many points as possible for the purpose of bringing back Izumi and Kurono. Either that or he likes the current team and wants them to get stronger waepons.