Season 3, Episode 7:
A Measure of Salvation
On the Cylon Basestar, Baltar is resting up after returning from his mission to survey the infected Basestar in the Lion's Head Nebula. He is confronted by Caprica-Six and D'anna, who both accuse him of knowing about the probe device and that he deliberately led the Cylons into a trap because he's still allied with the Colonials. Baltar protests, but Centurions enter the room and he becomes frightened.
A squadron of Vipers and Raptors are dispatched to the infected Basestar to investigate, and Lee and Sharon lead a group of Marines through the ship, where they find many Cylon corpses. Sharon finds a copy of herself who refers to her as a traitor, then tries to resuscitate the ship's Hybrid, to no avail. The group stumbles upon several dying Cylons who tell them about the probe and The Virus, and take an infected copy of Simon with them on their way out. Just after they leave, the Basestar self-destructs.
On Galactica, Sharon is kept separate from the human members of the team to monitor whether she was exposed to the virus, but it is revealed that she amassed antibodies as a result of her pregnancy and the birth of Hera. Cottle also goes over blood samples taken from the ship and realizes that they can't cure it completely, but can treat it.
In a room onboard the Basestar, Baltar is strapped to a chair and hooked up to various diodes and cables, and D'anna begins grilling him on whether he knows anything about the virus. When he says he doesn't know, she administers electric shocks, causing him extreme pain. In his desperation, HeadSix appears to him and tells him that she will help him, while Caprica-Six is appalled as she watches the torture, and walks off. HeadSix begins to take off her dress and make love to him as D'anna continues to torture him, and in his delirium, he shouts out that he loves her. D'anna stops the torture and looks at him in confusion and shock.
Bill, Lee, Helo and Roslin confront the dying copy of Simon, who tells them the Basestar stayed away from the rest of the Cylon fleet for fear of infecting it, and that Baltar was the one who gave them the coordinates for the nebula. Armed with this information, Lee devises a plan to destroy the entire Cylon fleet by executing the infected Cylons while Galactica is in range of a Resurrection Ship, although Helo considers it to be genocidal.
When Helo tells Sharon about Lee's plan, she says she understands why they need to do it, but agrees that it's something that has to be done. Bill, however, advises Roslin that he can't proceed without her presidential authorization because it is of an ethically-dubious nature. Roslin gives her authorization for the plan to be enacted.
Galactica jumps into the midst of a group of Cylon ships and begins engaging Raiders. Helo, still angered over what he perceives as unneeded genocide, goes to a power regulator and sabotages a set of environmental controls. Additional Cylon ships, including a Resurrection Ship, arrive, and Bill authorizes Lee to execute the Cylon prisoners. When Lee gets to their holding area, however, he discovers that they are already dead. Bill is forced to scuttle the plan, and jumps the ship out before more forces arrive.
Afterwards, Helo goes to Sharon and tells her about what he did. He maintains that what he did was right, regardless of the consequences. On Colonial One, Roslin meets with Bill and asks what happened. He tells her that someone sabotaged the environmental controls, which caused the Cylons to suffocate. Although Roslin wants to punish those responsible, Bill tells her to drop the matter. He points out that they're making progress towards getting to Earth, but they will have to be mindful of Baltar as well
- Absentee Actor: Michael Hogan (Tigh) does not appear in the episode, having become Achilles in His Tent.
- Continuity Nod: A Deleted Scene had Kara interrogating a copy of Leoben, much like her previous interrogation in "Flesh and Bone".
- Electric Torture: D'anna, when she tortures Baltar.
- Field Promotion: Helo has been promoted to Captain, while Gaeta has been reinstated to his former rank and position prior to the New Caprica arc.
- Good vs. Good: Helo's ultra-righteous views on the ethics of genocide runs up against Roslin's need to utilize every advantage the fleet can get (up to and including the mass death of all Cylons), to the point that the former sabotages the plan because of his values.
- Honor Before Reason:
- Helo scuttles a viable plan to wipe a large part of the Cylon forces off the map because he considers it to be genocide, and sabotages the plan on his own, which puts Galactica in danger.
- Likewise Sharon would rather be the last Cylon alive than betray Adama's faith in her.
- Karma Houdini: Helo gets off scot-free for his sabotage, even though Bill and Roslin know it was him who scuttled their plan.
- The Main Characters Do Everything: Lee is leading the Marines on the infected Basestar, as well as leading them to the Cylon holding area to execute the prisoners. However, this situation has an excuseit was intended to be part of a subplot where Lee joined the Marines to lose the weight he gained on New Caprica.
- Nice Job Breaking It, Hero!: Helo jeopardizes the fleet's safety when he sabotages the virus, and gets called out on it afterwards by Bill and Roslin.
- Oh, Crap!: Baltar being confronted by Caprica-Six and D'anna, and Centurions soon afterwards, over his ties to the probe and The Virus.
- Recycled Script: The episode takes large cues from the Star Trek: The Next Generation episode "I, Borg" (which Ron Moore also worked on as a writer), including the crew capturing an enemy combatant and planning to return them to their own kind with a virus in tow that will wipe them out, and all the ethical and moral concerns that arise as a result of it.
- Screw the Rules, I'm Doing What's Right!: Helo, to the point of jeopardizing the fleet.
- Self-Destruct Mechanism: The infected Basestar.
- Sickly Green Glow: The computer panels and other sources of light on the infected Basestar give off an eerie green glow. Moreover, the "fleshy" bits of the ship, which normally have a healthy red coloration, take a rotten, dark-green appearance.
- Strawman Ball: Lee arguing to commit genocide on the Cylons, because Tigh isn't available.
- Too Kinky to Torture: Subverted. HeadSix starts having sex with Baltar in his dreams as a way to ignore the pain caused by D'anna's torture. Conversely, he responds to the electric shocks by telling D'anna that he loves her, which freaks her out.
- War Hawk: Roslin, who in the first two seasons had generally been the voice of reason and morality, suddenly becomes very gung-ho about effectively using a biological weapon to wipe out the entire Cylon race. Justifiable, as her experiences on New Caprica probably didn't help her opinion of the Cylons.