I assume your question is why does he have to leave the room before the final discussion?
Well, he might have, as an active member of the IRB, a conflict of interest, meaning that he could be biased to vote in favor of his work which is incorrect, as researchers need to be objective regarding what they are studying. The National Academy Press. (2009). On being a scientist: Responsible conduct in research (3rd ed.). Washington, DC: Author. Is a great book you might read to understand the duties of any IRB and its members responsibilities, also the researchers' behavior. On it, is detail why a conflict of interest can guide to the decision of not conducting a certain research, independently of the undeniable reputation of Dr. Jones.
Yea i think its 3 too because in science i never heard them talk about Ancient Greece
