I'm in love with all the nature symbolism this episode had to offer. Especially flowers.
In the beginning and ending of the episode, Saki sees a flower called Morning Glory. I immediately associated this with the symbolism of "love in vain", which I thought was interesting as both times Saki sees the flower is around the time she see Satoru. It's also a shade of blue-to-red, which reminds me of Saki's nightmare in the previous episode. But even more interesting, I'm aware the flower also represents a single day for lovers to meet. Hard to honestly say who the lovers are in this, though.
The flower in the ending animation is probably a Red Azalea, which represents fragile beauty and toxicity. A symbol of Maria, rather interesting with the thought of how we've been told Maria was the cause of so many deaths. She's a very beautiful, yet deadly person, or so we're to assume.
The ending animation is something of a symbol of nature, with lovely images of the seasons passing and a clear picture of balance and life. It really suits Shin Sekai Yori, especially with SSY's seeming focus on Buddhism. I honestly wish I knew more of Buddhism, now, haha. It seems to have a large focus on Maria, and possibly her child as well, but it also feels like the entire meaning of the show in a short bit of animation. I love it.
Not much to say on the conflict of this episode, I'm just waiting to see how all this plays out. Seems like Maria and Mamoru will be in the next episode, excited to see what becomes of that. Oh, how harsh it is to have to wait for these episodes to come out every week, haha~

I'd say Maria and Mamoru. They are working with the Robber Fly colony in going after the unjust system that forced them to flee in the first place.

Yeah, that plus a previous discussion on this forum, and the ED for that matter, reinforces that Maria may become an Ogre. It's just my guess though.

A mindless Akki won't be able to help Squealer/Yakomaru. Maybe the people of the village will call her an "Akki" because she would be able to kill them but what if Squealer/Yakomaru has found a way to take away the death feedback and now Maria help him to take revenge on their twisted society, probably because Mamoru died and she blames the village for it...

Especially annoyed with the way they're treating these relationships. Goodness, you'd think Maria and Saki were intended to be the main pair at this rate. Seriously, that ending scene didn't even need to happen. It's starting to feel like fanservice, and it really makes things confusing.
I don't really like the intense focus on Maria, especially when they make her seem so out of character. Ah well;;
I'm also absurdly confused about Maria and Mamoru's child. That kid can't possibly be old enough to be a cantus user yet, considering the time it would take to conceive a child and all. Maybe I'm thinking too hard about this, though.
This episode was fine overall, it just felt really lacking.

It seems that the cantus comes in at around the same time as puberty, or atleast, is linked in some ways. If it really has been 12 years as said in the end of the episode its not impossible. It would also explain why they only suddenly just had the ability to use it. If mamoru and maria had sex soon after they elft the village (like saki and satoru) then give it 9 months and leaves the kid around 11 which I think is reasonable. It also explains why the user is monstrously powerful, remember how strong saki was shown to be before it was initially sealed?

That said, that relies on mamoru not wussing out of something like having sex with someone. I dobt shinji ikari mk 2 could do that...

What did you think the weird blue light/woman out of the dead guy was?