All Tengan has to do is fuckingTAKE RYOTA'S PHONE
alsofucking FF base happens to have a tower that can broadcast a signal to the entire WORLD (holy fucking shit this is dumb) and chisa gets her hands on the suicide brainwashing videos and she GIVES THEM TO TENGAN!? WAT. why the fuck wouldn't she immediately upload that shit and have everyone commit mass suicide?
If everyone is dead, there wouldn't be any despair, duh.