But why would Gantz then let people die in the first place?
If he was there to prepare mankind for this invasion, it seems dumb to cut the number of his own defenders.
I just got the thought that if it is true that the data to build the Gantz Balls was sent by someone to prepare humans for this huge attack, maybe this Game-Character of Gantz (calling the participants stupid names etc.) was added by rich people/companies, whoever, who got the purpose of this...