Previously: When last we saw P.R. rep Aaron Doral (Cylon Model #5), it was waaaaay back during the Miniseries. He was thrown off the Galactica and stranded at a munitions depo.
He (or one of the models that looks like him!) is back! And he has a snazzy belt made out of explosives, which he uses to sneak on to the Galactica and blow up an unspecified hallway. While all this is happening, the Chief and Boomer #1 are doing it in what looks like the Galactica swimming pool. (They have a swimming pool?!? Was that included in the water shortage count?)
This prompts the reluctant admission to the Master-at-Arms (Sergeant Hadrian) that Adama and Tigh knew all along that Cylons have evolved to look like humans. She requests a tribunal to be called to investigate the breeches in security aboard the Galactica. She also suggests telling the rest of the fleet that the Cylons look like humans.
Tyrol catches a bunch of his crew putting together a still in a supply closet. He tells them if they're going to do something stupid and dangerous, they might as well do it right, and gives them instructions for how to properly make moonshine.
Roslin definitely does not want to tell the public that Cylons look like humans now. She insists that an independent tribunal needs to find a fall guy so the public doesn't go apeshit. Meanwhile, Sergeant Hadrian's investigation focuses mainly on Chief Tyrol and Boomer #1 (the "real" Sharon.) All of the deck crew tries to cover for Tyrol and it ends up biting him in the ass, as no one's story matches.
A press conference is called, and Roslin tells everyone that Cylons look like humans. She shows mugshots of Doral and Leoben (the Cylon that Adama kills in the miniseries.) Everyone promptly freaks out.
Hadrian brings Boomer, Tyrol, and some of Tyrol's crew in front of the tribunal. Boomer flat-out lies about screwing around with Tyrol. Tyrol learns that a hatch was left open on the hanger deck, and that's how Bomber Doral got on to the Galactica. When Hadrian presses him about his affair with Boomer, Tyrol pleads the fifth. (Only, in Colonial law, it's pleading the 23rd.)
One of Tyrol's men appears in front of the tribunal, and confesses to going through the same hatch that Boomer went through to sneak off with Tyrol. Only, he decides to cover for Boomer, and takes the heat for deliberately leaving the hatch open.
Dr. Baltar visits Starbuck in sick bay. Starbuck points out to Dr. Baltar that the bomber explosion occurred near his lab, and was perhaps the Cylons trying to stop his "Cylon detector program." Baltar freaks out about this to his imaginary girlfriend, Number Six. She puts him in a choke hold and tells him to suck it up and finish the detector. That's... one way to get what you want, I guess. Maybe the Cylons haven't evolved enough to learn about withholding sex.
Adama is called in front of the tribunal, which he is not happy about at all, especially when Hadrian gets uppity about Boomer & Tyrol's relationship. Adama calls the investigation to a halt, as it's become less of an inquiry and more of a "witch-hunt" to find out who's a Cylon agent. (We find out that Adama's father was a civil liberties lawyer, which will be something you won't be allowed to forget in upcoming seasons.) Hadrian tries to arrest Adama for interfering with the tribunal, and Adama insists that Hadrian be confined to her quarters. Adama wins, and Hadrian is taken away.
A press conference is called, and this time around, Tyrol's crewman Socinus (the one who said he left the hatch open) gets to be the scapegoat, and is stripped of his rank and thrown in the brig. This doesn't sit well with Tyrol, and he tells Adama that he deserves to be the one thrown in the brig. Adama tells him that he needs to man up (and zip up), because he's needed on the ship, not in the brig, and not down Sharon's pants. Tyrol goes directly to Boomer and breaks up with her. She does not take this well. Mostly because he sort of accuses her of being a Cylon and purposefully leaving the hatch open. Kind of blows the "it's not you, it's me," excuse, Tyrol.
Meanwhile! Back on Cylon-Occupied Caprica: Helo goes looking for missing Boomer #2 (the other Sharon,) which shows the Cylons that he really does love her after all. They arrange for Boomer to be "rescued" by Helo (but not before Number Six knocks the snot out of her, to make things look "authentic.") Unfortunately, this show of love puts stars in Boomer #2's eyes: she now has actual feelings for Helo. (Or, as "actual" as a Terminator can get. Judging by certain scenes in T3, all it takes is a reboot and running scan disk.)