They were forcing the virus to one's body and forced the body to have the proper reaction to strengthen one's body.
William could still remember the experiment that was done in the middle of City V15 back then. It was such a gruesome experiment directly done onto human without caring about the risk that it might affect their body permanently or even kill them. They didn't have the permission as they tricked the survivors there.
His hand tightened at that thought as William resisted the urge to slam his fist onto Professor Hose beside the cowboy man. They were both only at the lowest rung of the chain command and probably also being used by other people.
The bumpy journey was silent.
With such an incident, it was clear that no one was in the mood to talk merrily with each other anymore. When the bus stopped, William also brought Gloria away like an older brother who was caring of his little sister.