I think we all repeat our worst mistakes less out of some weird Freudian masochism loop than the simple animal desire to get it right this time: again and again, until we get it right. The difference is a mile wide; it's the difference between kindness and self-hatred. Between "This has all happened before" and the shape of things to come. A closed system lacks the ability to renew itself; knowledge alone is a poor primer. It takes an angel to push you over the edge, sometimes.
Boomer balks when he takes Hera from her, but he tells her not to worry, and takes her around a frosted-glass wall. "There, there now. You'll have all sorts of new playmates pretty soon," he says, and Boomer weeps as Hera turns and puts her little hands against the glass, calling out again and again for her new friend.
Bill's got tears in his eyes as surveys the damage, heading back to his quarters for the first time since before the latest accident; he takes off his Admiral's insignia before he even gets inside, holding them in his hand. She groans around him, in dreadful pain. This isn't how he wants to remember her. The hatch isn't even locked, it swings easily open. In the bathroom, the panels have fallen off the walls. It's an unholy mess. He picks up the whitewash and tries to paint it, just like Boomer when her home was dying all around her; just like Kara, too. He splashes the walls with paint, great gouts of it, and collapses against the wall, caressing her, smearing his hands across the bulkhead and crying out, saying goodbye. It's a funeral. He blinks; she is his world.
Kara pulls up tankside, Hera's notes and her slick music in hand. The lights are up normal this time, but he's still gone. "I know you can hear me, Sam. Just like I know on some level you'll understand. Same as the old you. Just took me a while to accept it." (That is a characteristically Kara apology, isn't it? "Sorry I tried to shoot you in the head, but like, you were so freaking me out. Don't worry though, I've totally worked through it.") "Which brings us to the larger question: Why am I here? I think it has something to do with this music." You can feel Sackhoff struggling with the lines, as she always does when there's a false note like this Chester Copperpot cool-shit little-boy nonsense, but it's good that she's so good.
"There's a pattern there, a pattern that I can't see, but I think that you can." As much as I hate the sheet-music thing, I like this moment: if you're looking for patterns, that's both computation and intuition. We know she knows that, because we've seen her do it before, so we know if she wants help it's the right idea. And who better to ask than your robot husband, who is both a computer and connected now to God Himself? Patterns are all he's got now. Not to mention the lovely reversal of having Kara play Leoben to the newest (hybrid) Hybrid of all, assuming his role here as she's assumed so much of the work he used to do for her. "So we are going to sit in this room until we figure it out," she says sweetly. He doesn't move as she plugs him in and says, hands-on-hips pragmatically, "Talk to me, Sam." Everything spazzes out, and then he chills and starts to sing: "New command." She stares down at him, with almost a smile. He blinks and the world trembles, but he's Sam.