Battlestar Galactica S03E06 - Torn

Baltar learns from Caprica Six of their ability to project themselves and imagine different surroundings which leads him to wonder if he too is a Cylon. He has told the Cylons what he knows about the location of Earth and they dispatch a Basestar to investigate. In the end, the survey ship is infected with a virus killing everyone aboard. Aboard the Galactica, Lt. Gaeta has been reviewing Baltar's work in deciphering the map they recovered on Kobol.