I don't think Yui broke down, I can see clearly that her desire to go rampant did not subside like with everyone else, this is magnified by the fact that she is in fact in love with that idiot of a boy. Her fear of boys is turning her into a raging spirit, and she is in fact a danger to everyone around, which is why she is secluding herself. I don't think Heartseed expected that, and seeing how this is going all serious mode, the next ep should conclude this arc. Which makes me wonder what will happen with them next time.
Inaba yet again is the scariest bitch, her inner desires are very violent, it shows that she honestly hates that part of herself. I'm pretty sure she masturbates often in this situation, taking into account her desire for taichi.