The first thing to realize is people are asking the wrong question. "How do I get to fuck Quinn in Ep6?". Wrong question. The fucking comes later. The question that should be asked is, "How do I get Quinn to trust my MC and open up to him, even just a little?" Because that's what this is about.
When the mc offers Quinn help, she's not thinking, "OK, do I wanna fuck this guy again?". She's thinking, "Do I wanna lower my guard to this guy?" Of course she doesn't consciously think those words. People who have built a barrier around themselves subconsciously push people away, either by withdrawing (KRJ, sorry guys, she's gonna be a lotta work) or in Quinn's case, an aggressive, spiteful exterior.
Of course it's just a computer program so we can look at the variables to see what makes up the logic, and if we take those few conditions as standalone states that have no bearing on the mc's personality, it can lead us to question the logic.
But it's not that simple. Not for someone like Quinn.
Quinn accepting the MC's help is her opening up and trusting someone. That's not something she does. Even Riona, her closest ally, is often treated as a subordinate. Sage, her HOT mother, she keeps in the dark half the time. Tommy, her "friend"? She doesn't even tell him that she's ditching the DIKs big end of Hell Week party for the prep party, even though Sage told her to tell him or Rusty.
So who would she let her guard down to, for them to help her? Who does the mc need to be for Quinn to lower that guard. He needs to be someone she likes, and someone she feels she can trust.
Who does she like? She likes DIKs. Which ones? Certainly not the beta DIKs which make up most of the fraternity. She likes the kinda DIKs that take charge, handle shit, basically an alpha.
Who can she trust? No one.
When the mc said those words:
"Come with me, let me have a closer look at it."
She responded with:
"I don't need your help."
Of course she did. It's Quinn. Already putting those defenses up.
But here's the kicker. It wasn't Quinn that made the next step, it was the MC.
The MC who isn't a DIK by nature, or who's all wrapped up with M&J, or who never fucked Quinn on the DIK roof, that guy, he pathetically responds with:
"Hey! Wait!"
"Quinn..."
As she turns and walks away.
But the true DIK, who knows this girl, and isn't caught up in some convoluted threesome with a bunch of high maintenance drama queens, that guy, he doesn't wait for Quinn to walk away, he responds with:
"Yeah, I get it. You're strong and independent."
"Bravo! Do this for me."
And Quinn drops her guard for a bit. And the rest is history.
So it's not about Quinn being omniscient and knowing whether the MC is in a relationship with M&J. It's about the mc being more assertive at that moment in time. And the MC is the sum of all his actions and experiences.