Near the beginning, the group along with some other students escape onto a bus to avoid the zombies. Shidou, a teacher, has ambitions of becoming a "god" over this new world and has to start gathering followers.
So, what's the best way to win over the trust amongst a group of terrified teenagers? He initiates a orgy between all of the students.
After they get done satisfying themselves, he makes one hell of a speech and wins them over.