Tu Quoque, Red Herring or just Deflection?

Well the ad hominem attack was that "you accuse me of being two-faced when YOU TOO are two-faced", and "tu quoque" in latin means "you too", so it was not just any personal attack ('you're ugly, lazy ets), he accused her of doing what she accused of him. So it wasn't completely irrelevant to the initial argument to consider it just abusive. And also, he didn't explicitly deny the accusation, just deflected. 
Also, another question: If Ad Hominem abusive is "derailing the conversation" then what's the difference from Red Herring? Or is it that Ad Hominem Abusive IS a more specific form of Red Herring?

Well the ad hominem attack was that "you accuse me of being two-faced when YOU TOO are two-faced", and "tu quoque" in latin means "YOU TOO", so it was not just any personal attack ('you're ugly, lazy etc), he accused her of doing what she accused of him. So it wasn't completely irrelevant to the initial argument to consider it just abusive. And also, he didn't explicitly deny the accusation, just deflected.

I understand, but bearing in mind that the whole dialogue is in the context of his violation of the rules and improper eating, with which her argument is connected, he did not accuse her of that but of hypocrisy. And if the dialogue were taken separately, then it could be interpreted as ad hominem (tu quoque) .

As for your second question, the difference between these two fallacies is usually "felt" in that by attacking a person we try to end the argumentation by assuming that the facts we present are enough to refute what the opponent is saying (although we don't always say it). Red herring  , on the other hand, is an attempt to move the debate to another area where we can more easily defeat our opponent.

By the way, I have to say that you think like a real logician, analytically and strictly determining all concepts. Informal logical fallacies are not so easy to strictly define, we can take them in a narrower or broader sense, if we take them in a broader sense, there can easily be intersection and subordination between fallacies.

Despite this, I think that studying logical fallacies is a good way to improve our own reasoning, avoid deception, and remain guardians of the truth.

It is interesting that in the study of logic, beginners are sometimes more thorough and better base their views taking into account the details than the experienced ones.

[To Shockwave]

Thank you for your kind words. You read me correctly. My profession is computer programming, so I'm used to analyzing everything and paying attention to small details (and I had a predisposition to thinking analytically since I was a kid).

Thank you also for pointing out the distinction between Red Herring and Ad Hominem. That made sense.

Now to our point :)
The woman didn't accused the man because of eating the extra food, the accusation wasn't about the action itself - at least that's what she said on the outside. She accused him of betraying their trust - I don't know what was in her mind because she didn't finish her train of thought. But she started mentioning another relationship of hers (probably because her conclusion could not be proved by the food incident alone, so she wanted to use her experience as proof), and the main accusation was that he was a person that behaved like her previous relationship who behaved differently in front of others and differently behind their backs - the food incident was just an incident that verified her belief. 

So I think it is more complicated actually. I'll try to cover it
1)So she accused him of not being worthy of trust because he was two-faced. He then accused HER of not being worthy for trust.
 She accused him that other people (the players) couldn't trust him. He accused her that other people (her boyfriend) couldn't trust her.
  That would be the "Tu Quoque" part
2)She accused him of not having the moral values that she has. He accused her of not acting according to those moral values (of honesty and trust).
So now we also have him accusing her of double standard (when he makes something behind their back she accuses him of being untrustworthy, but when she does something behind her boyfriend's back then she is virtuous.
3)Since her boyfriend is not there to know whether the accusation is valid, and since some intimacy was indeed shown in the camera, she claimed to be just a little more close, but she knew that even a suspicion could harm her relationship, so it wasn't adequate to request from her accuser to prove the accusation but she had to prove herself that she was innocent (so she was kind of forced in those circumstances to do it i.e shifting of the burden of proof )
4)And finally since the subject changed from "You are two-faced" which in an honest conversation would end with the man conceding "Yes, I am two-faced/No I am not", the conversation changed to "You were cheating on your boyfriend" which would end with the woman confessing "Yes I were/No I weren't". And that's red herring 

So it was a really sneaky, really calculated and ultimately really effective chicanery, effectively shifting the focus from the accused and reversing the offender and the victim and having the woman striving to prove HER innocence, utilizing a whole armory of fallacious tactics.

But back to my initial question, I wanted to know whether the first point would be categorized under the Ad Hominem, because the proposition of the argument was not explicitly stated. For example I would say it is Ad Hominem if the guy said 'How can I be immoral when I act as "deceitfully" as you but you claim yourself to be virtuous? Since we both have the same degree of deceitfulness and you claim to be virtuous, I am also virtuous.' That's an explicit argument. But he didn't do that. He just moved the conversation to "Should your boyfriend be wary of you? Can he trust you?"

Kudos if you managed to make it through to the end :)