Ajo is a sick creeper, doing that to her daughter... But was that the real one or the robot? He opened her up like it was nothing and was talking as though she needed to be given fuel or something (''we need to replenish her'')... Either way, that guy is a fuck.
Sergei failed to retrieve Key and he got some fancy injuries to boot. Plus those robots got both smashed. In this episode he and Wakagi talked a bit about what was driving the robots crazy. Partly, it's because of the user's emotions, so Sergei has been at fault all along. The other part is Key (nothing new there), who I think was subconsciously controlling the robot in this episode.
Still no clue about that priestess woman in Key's mind. This time she was with a baby. Perhaps she is Key's biological mother and Key is some mixture of robot and human, but given that Key is first robot and second human I'd say the robot was done first and then the human parts were attached... It sounds like bullshit, especially given that those organs would have to grow, but that would explain why her body model was changed a few times... Maybe. Anyway, that's what I've got for now.
The religious leader won't be having much of a role from now on it seems, kind of disappointing. Not the character himself (he didn't seem like much from the beginning), but rather his usage. I guess it's soon to judge though.
Tataki is kind of like John in Sci-Fi Harry, involving himself and going with the flow even though he's unrelated to what's happening. Sakura would be Catherine... And sadly we've got no Chinori.
Well, it seems Sakura is now willing to help Key out. They're seriously going with the idol idea? Uh... suit yourselves.
More strange voices being heard in Tataki's apartment, it's definitely Miho as you said. Still don't know what kind of role she's actually going to have in this story.
Hmm, I must say I was expecting something more epic or involving or compelling out of this show given the few comments/reviews I took a look at. Still 6 eps + 2 movie-length final eps to go, so hope for improvement is not lost just yet.