The first half of this episode is largely dialogue driven as characters reflect on events that had occurred earlier. For example, Yuto and Satsuki follow up their conversation on the ethics of killing while on a date. It's not your standard date fare, I'll admit, but these are two people who are dedicated to ending the world. If anything, the fact that they are establishing an emotional connection is more of a shock than anything else.
Said emotional connection makes Beast rather jealous, because of course the AI goes insane. It's a somewhat predictable plot point, but it could have been done well. Alas, it falls flat, especially coming on the heels of Iggy's amazing face heel turn.
Meanwhile, the Dragons of Heaven lament Sorata's injured status and try to figure out why Arashi went AWOL. Yuzuriha seems to take it the hardest, but Karen manages to comfort her.
From there, the episode puts more emphasis on action as Aoki and Yuto bump into each other on a train. I actually rather enjoyed the chummy dialogue between them before they engaged in the inevitable battle.
While Aoki does get the upper hand, Satsuki manages to convince Beast to come to his aid and incapacitate Aoki. Luckily, Karen's there to come to Aoki's aid and the two dragons have the rematch that was promised in an earlier episode.
As they deal in fire and water, it's no surprise to find that they are an even match. I have to admit, it was rather shocking to see Karen just set Yuto ablaze and just flat out incinerate him. It doesn't work (apparently Yuto is made of water? what?), but it was still a shocking scene to say the least.
Just as Yuto is about to drown Karen, she pulls a Vegeta and creates a massive explosion to take him down with her. Unlike the Saiyan prince's effort, her's is successful as Yuto does die, though she dies as well. Karen is OK with it, though, because Aoki will continue to live. That makes, what, six characters to sacrifice themselves? It's getting a little ridiculous, I have to say.
As the episode ends, we see that Satsuki was killed as a result of her connection to the yandere Beast.
With three major characters dead, this episode certainly succeeded in thinning the herd. Personally, I wouldn't have minded seeing all seven Dragons of Heaven face off against the Dragons of Earth in a massive brawl, but I guess they're going more for a solo confrontation between Kamui and Fuma. We'll have to see how things play out from here as we get closer to the final battle for the fate of Earth.