If your boss expects you to work while having food poisoning/vomiting/diarrhea, just throw up in plain view of customers or on the boss. If they truly think you are “faking it”, then vomit on them.

How can they argue it's all fake? I mean, what type of control freak even does that? As a customer, I want to know if the manager is making people prepare food while vomiting. it's unsafe and violates food safety policies.