for whatever disease he chose to inject to himself. I mean, if the zombie ignored him it was because he was already sick, right?
so the disease symptons should have been there?
I'll be good I swear... I'll never see a movie ever again.
They could "smell" it apparently. They wouldn't have noticed symptoms.
One of the scientists noted that there was already a precedent for it in nature. Predators would avoid certain animals if they smelled some disease or illness, choosing a healthier victim instead for a meal.
Of course there are other predators that do exactly the opposite, targeting the weak, ill or dying as much easier prey to catch and kill.
Mother Nature is a bitch.