As I understand it: Helo was left alive so that he could fall in love with Boomer. He had to, or he would be killed. They tested him by kidnapping Boomer, beating her up and waiting to see what Helo would do. He went back for her.
Helo & Boomer eventually had spine-glowingly hot sex. The next day, or whatever, as Six & Doral were waiting nearby for Boomer to report (I guess they don’t have built-in modems?) Six says, “Sharon’s late.” Hee! Anyone else catch that? Anyway, Sharon shows up, says “we had sex,” Doral looks, I dunno, either rapturously happy for her or possibly a bit snidely jealous, after all, Helo does look pretty hot in those space pants, or who knows, maybe he’s got a thing for Sharon. Heck, who doesn’t have a thing for Sharon, gay straight, male, female, Cylon? We all want her. Except Six. Six seems to really have a case of the ass with Sharon. She probably wants her too, though. But I digress.
Anyway, Doral tells Sharon they’ve set up a cabin nearby with food, supplies etc. and she’ll have to convince Helo to stay there and play house and give up his quest to get off the planet & find Galactica. If Sharon can’t convince him, she’s to kill him. At that point, Sharon, in apparent conflict with her programming decides she’d rather take off with Helo and make sure he lives than, I guess try to convince him to play house under the watchful eyes of the overseers. In any event, she has no intention of killing him, or allowing him to be killed, even if it means shooting her own sisters. It appears she is willing to go ahead with Helo’s plan of stealing a ship and getting off the planet.
So that was the plan. You probably weren’t asking for all that, but what the heck. Can you tell I like talking about BSG, and don’t have anyone at home to talk to about it?
We’re left to speculate: Why’s it so important for Helo & Sharon to play house on Caprica? What plan did Sharon have for when they eventually did get off Caprica? She can’t exactly just show up on the Galactica, unless she’s got a really good plan for convincing everyone that she’s the real Sharon, and the other one is the fake.
At least now we know that if they do get their hands on a Cylon ship, they can FTL that sucker pretty much as far as they want. We also know that BSG takes place in a strangely shaped galaxy where the only direction you can go is more or less towards Kobol, so catching up with the Galactica will probably be easy.