They found you eating a dead human. They think you are a smart zombie, one than can mimic human behavior. They are keeping you alive... for now.

You're human. You can't let them test your blood because you've been experimented by the government and it would screw up the test

Guy: Oh, so you're finally awake. Interesting. I hope you're not too uncomfortable in your restraints but I hardly doubt a zombie feels much of anything

Girl: Hello. Do you understand what we are saying?