I don't really get your point here... I mean "MC's true self" is completely dependent on your choices and if you make it to the end of EP9 still on the Jill Branch in the first place, "the real MC" is already permanently set to either Chick or Neutral. And Jill already accepted that crazy shit went on during Hell Week. She even accepts MC's explanation of why he punched Tybalt (if you punch him) and laughs at the dick pic in Tybalt's presentation. Hell Week itself is not a deal breaker for her unless you choose to make an ass of yourself.
Her opinion of the DIKs stem from earlier interactions with Rusty and his friends (probably Tommy and Vinny). The fact that she knows what the DIKs can be like and still wants to get to know them means she's already accepted them. So the suggestion that she hates MC's friends is completely wrong. It's pretty clear in the dialogue at the end of the episode.
Yet she makes snide comments about MC's best friend Derek.
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His point is that MC's 'true self' doesn't differ that much between LI, unless he is with Jill. Check his bios entries, he doesn't have sex with her,
he makes love. Jill is the only LI he protects from the walk of shame and in the most corny way by giving the diks a speech about 'his girlfriend' etc. And just like
noctarima said, its not that Jill is twirling her landing strip mustache manipulating the MC, its just her demeanor and MC's inherently trying to please her that make the MC act so different. You might not mind it, but you can't argue its not noticeable.
Nick was disguised as an evil clown, right?
He was the first one to get to the basement to fix the blackout and the scene where the MC looks at the installation again is really weird.
Was he? I only remember JB and Jacob being there. EDIT: Yup he is there.
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The problem I have with the 'Nick is the traitor' is that he is way too easy of a pick. Being a red herring is my prediction.