Making one of the regular cast members a Cylon was a brilliant idea on the part of the writers, and even more brilliant was the idea that her Cylon nature was repressed so far down in her subconscious that she didn't even know it was there.
For the individual, this concept is terrifying. It prompts perhaps the most difficult questions this series has asked as it pertains to human existence: What's our responsibility for harmful things hard-wired into our nature? Can we overcome them? We cannot change the circumstances into which we were born; all we can do is take control of our actions. But what if we were like Sharon Valerii, who wants to be a good person, but is taken hostage by an alternate personality who inflicts harm on others? Who is the real Sharon, and who is the impostor? It's a question we sometimes ask about those with certain mental illnesses: Are they responsible for violence if they have no ability to govern their action based on its possible harm to others?
Personally, the feeling I have for Sharon, more than any other feeling, is pity. She's the most tragic figure on this series. Her character arc has moved her from fellow military comrade and Tyrol's lover, to suspected Cylon infiltrator, to reviled traitor and assassin, and now, finally, to a death that many, it would seem, welcome. At every stage in this arc, Sharon has been all but helpless — a victim in a universe designed to use her for its own purposes and then destroy her. Her only way out would've been suicide — which she tried, and failed, to accomplish in "Kobol's Last Gleaming, Part 1." Baltar told her then that life could be a curse. There's absolutely no doubt about that if you're Sharon Valerii.
What's so compelling about this character arc is how, in the powerful "Resistance," we see the uncompromising ugliness in how her former friends now regard her. With revulsion. With threats. With violence. With an utter lack of any sympathy or understanding for what we know is a more complicated situation than what the characters are permitted to see, either through willful blindness and disgust, or through having less of an entrance into Sharon's mind than we, as viewers, are permitted.
Of course they feel betrayed. Wouldn't you? If you were Tyrol, and found out you had been in love with a machine, would you be able to now extend forgiveness to that machine? Or would you assume the machine was simply playing you for a fool? The troubling thing is that she was ... and yet she wasn't. The tragic definition of Sharon is that she was played for a fool by a part of herself. She's as much a victim of herself as everyone else was.
Tyrol has a right to be angry. Because he was having an affair with Sharon, Tigh now suspects him of being a Cylon. In the opening scene, Tigh interrogates Tyrol and isn't the least bit nice about it. In Tigh's mind, Tyrol is guilty by association. One has to stop and ask oneself what law and order have come to when someone can be guilty solely for a relationship and not for any specific action or knowledge. Tigh openly drinks from a flask during this interrogation, perhaps suggesting that alcohol is his right in a room that has no rules.
Besides, Tigh has other problems. Ships in the fleet are beginning to protest martial law by refusing to make supply runs to the Galactica. Facing the prospect of civil unrest, he considers sitting down with the other ships' captains and giving them reassurances for why he had to declare martial law. But Ellen privately talks him into taking a more draconian tack. So Tigh sends Raptors to board the ships and seize the supplies, which results in rioting, and military officers losing control of the situation. On one ship, four civilians are shot and killed in a melee, which Roslin labels a "travesty." It's a travesty, all right, albeit a completely accidental one.
Interesting here is how Ellen goads Tigh into heavy-handed actions that he otherwise might not take. She manipulates him into being a stern hard-ass when, really, he's wracked with uncertainty and doesn't want to be in command at all. Yet Tigh willingly lets himself be manipulated. Their marriage is one of bizarre codependence, where sexual fireworks arise from angry alcoholic dysfunction and shouting matches. This cannot be healthy.
Tigh's drinking and questionable leadership lead other key members of the crew to start plotting ways to undermine him. It's a covert mutiny; Lee wants to break Roslin out of jail before things get any worse, and he has the support of Dualla and, obviously, the entire flight crew. With some quiet, careful maneuvering, they plan to get Roslin off the ship and hide her in the fleet. Even Tom Zarek is recruited for this effort, since he's likely to know enough nefarious people to get the job done. "So, the enemy of my enemy is my friend," Roslin notes dryly.
What I love about this show is how you can't predict exactly what's going to happen, or what the characters are capable of doing. There are nuances to be found and choices, big and small, for the characters to make. Take, for example, Lt. Gaeta. He doesn't agree with the prospect of mutiny or undermining, and he notices Dualla's off-log transmissions. But watch Gaeta's reaction when Tigh asks him if he's noticed anything unusual. Similarly, listen to Billy when he decides not to get on the ship with the president. What he says makes sense, but I wouldn't have expected it given his typical steadfastness.
Even Adama finally waking up took me by surprise. Just when things start to really look bad for Tigh (he knows he's made some bad calls), Adama walks in and provides reassurance, vowing that they'll "pick up the pieces together." The writers kept Adama out of action just long enough for his return to have a perk-up effect.
Or take the episode's dramatic highlight, where Baltar has been assigned to clear Tyrol with his Cylon test, and instead ends up interrogating Sharon. He injects the chief with a deadly toxin, and threatens to let him die if Sharon doesn't tell him how many Cylons are in the fleet. Sharon doesn't know. But, you see, she does know; the information is just hidden from her, retrievable only as a last resort. Faced with the prospect of her former lover dying, she finally cracks and reveals that there are eight Cylons in the fleet.
This scene is acted and directed with chilling urgency, and provides another example of the dark and intense places Baltar can go when he's sufficiently motivated. Interestingly, this also shows how using love/sex as a weapon can be a two-way street. After season one showed how the Cylons could manipulate humans — how Six manipulated Baltar, and how Helo could be manipulated into impregnating Sharon — this scene turns the tables, with Baltar using Sharon's love for Tyrol against her. It's cruel and heartless — and sublimely perfect.
Things get even darker for Sharon when it's revealed she will subsequently undergo mental and physical tests. "Like some kind of lab rat?" Tyrol asks. Yes. Baltar has a unique perspective on all of this given his own relationship with a Cylon. He tells the chief to be glad he experienced love at all — "even if it was with a machine." The notion of Sharon becoming a lab rat flirts with the depths of human ugliness when you stop to consider that this is a sentient being with real feelings and emotions, and at one point was a friend to many people on this ship. This is great, awful stuff. These are tough questions for impossible situations, and with scary answers.
Significantly less tough and less challenging is the adequate but far more obvious action-and-machine-guns material on Caprica, where Starbuck and Helo are shot at by humans who think they're Cylons. They eventually team up, and we learn that these humans are a part of a group of resistance fighters hiding on a base unknown to the Cylons. It's nice to finally see other people on Caprica. The story plants the seeds for Starbuck's obvious new love interest.
Possibly the biggest unexpected choice in the episode is Cally's, which is shocking in the same way that Sharon shooting Adama was shocking. Cally, after going through hell on Kobol and now watching the chief go through hell in being jailed, seems to have snapped. In a moment of venom and hate, she walks up to Sharon (as she's being escorted through the corridor) and assassinates her Jack Ruby style. Sharon's dying words are "I love you, chief"; Tyrol's anger is stripped away by the truth that he also once loved her. The moment reveals an honesty that cannot be denied.
Perhaps something to be pondered here is that guilt or innocence is a matter of intent. The puzzling question is what Sharon's intentions really were. Her intent might've been buried under what we only perceived as her real personality. Perhaps the person was a veneer and the Cylon programming held all the marching orders. And yet, when you look back at "Water," you see that Sharon could resist that voice and act on her own. It's an unsolvable puzzle, and the episode has no answers. The only hint comes in the form of a strong image — a drop of Sharon's blood hitting the floor, echoing a shot from the beginning where a drop of Tyrol's blood did the same.
The Cylons bleed, just like us.