I'd bet
Random Flaw.
Obviously that's what is happening, Yui is usually a non aggressive person, she would back away from conflict, her flaw is insecurity and anger. The blonde guy (pardon for not remembering the name of a guy that is of no interest to me at all) is very possessive of Yui, when Yui was surrounded by police he simply snapped without thinking.
Iori has a lot on her mind, trying to discover her true self is a ruse, she wants to step away from Taichi because she realized she is also incredibly possessive and jealous of Taichi, she showed it briefly but for some reason she seems to be able to withhold her frustration for now, she called him the previous evening in her jellous mode and quickly calmed down by simply hearing his voice.
Inaba is not the most dangerous in this situation this time, she showed her affection to Taichi several times, and Taichi is well aware of her feelings, he isn't ignoring that fact either, in fact he's battling her pick for a fight with neutral character showing lack of interest in "lovey-dovey arguing" if you know what I mean. This means Inaba is relatively safe as long as she can hold out for a while. Her problem is however that she is well aware of the dire situation she is in, she is not just in love with Taichi, she is madly in love with him, her confession about masturbating to him is proof of that. Inaba however has a very strong will and she will try to hold back as long as possible and longer. She will not try to make any more moves on Taichi because Iori is her dear friend and she will not want to ruin that friendship.
Her will is what makes her dangerous only to her, she will eventually wear herself out by the end of the arc. If nothing happens between those two it will be a miracle, if Iori doesn't find out or somehow accepts it and forgive the fact, it will be more of a miracle but I think Taichi will not hide it from her.
And this is where I come back to:
Well, this episode brought some nice situations aswell.
Havoc, you are right about inaba i think this change will create some new problems between yui inaba and nagase.
By the way i wonder what were they talking about at end (nagase and taichii)
Iori wants to take distance from Taichi, making room for any possible "Inaba Assaults!"
This means Iori knows and accepts anything that Inaba might do and she is willing to forgive her anything that can possibly happen, also by distancing herself she will attempt to be less jealous and possessive of Taichi, where i would like to explain that we still know very little about Iori's personality other than the fact that this situation may be very Fatal to her.