Well, I wouldn't necessarily add this episode to the "Suou Molestation Gallery" since Hei didn't actually touch her chest in accordance with the previous 2 episodes........... :lol:
And yes, the Yin line Hei says at the end is
*talking to Mao*
"Yin......."
"I'll kill that woman."
I doubt it was anything Yin actually did herself, but something Hei thinks he needs to do because he has to, like because she was brainwashed or is being controlled or something, which would also explain his turn to the Hobo Side; he doesn't want to kill her, but feels he has no choice for whatever reason, which has thrown him into this depression.
Which means she's alive. Which also means she can be saved.
And I don't see where the idea of Suou replacing Yin is coming from; the end of this episode made it perfectly clear that Yin is still vital to whatever is going on here, or at the very least to Hei's character. And Suou is an entirely different character; she wouldn't be able to replace Yin's role in the story. I don't actually expect to see her until maybe the last few episodes though, probably similar to a "final boss" introduction.
I don't really see the Tannya hate either; there has to be something more to why she's changed so
radically beyond her will. Compare her now to how she was in episode 1, and she's an entirely different person.
Although I can't really see why July went with him, either....