I'm a little late to the party but better late than never, right? One thing that seems to be mentioned several times - and forgive me if this has already been mentioned - is that Tanya has mentioned several times that she can not find any differences between the zombie's skin and blood samples and her own. Has she had a chance to compare them against another person's samples? I'm not sure if that is relevant but if there IS some sort of infection or latent immunity to the zombie disease (dunno what else to call it) then wouldn't it make sense that her blood would look the same as the zombie's? This could be more proof of that immunity.