He doesn't know what Foster is talking about. There's too much, to many words that have so much meaning to the human that don't mean anything to the Psionic. He doesn't know about human diseases or rotting or who lied about what. He at least knows though, that he isn't a liar, and if that's what he has to focus on to continue this conversation he will.

"I'm not lying." he says the last word spit through his fangs. Foster's emotional display is effecting him, making him tense whether he understands the reasons for the feelings or not. He feel's like he's cornered a wild animal, and it's chosen to fight for it's life rather than flee.

"Lots of people have diseases, that does not make you a disease, it's just... It's just logic! Common knowledge! Fact!! Disease is caused by something, people don't have a cause."