Cersei is a good comparison. She was always so focused on herself and what's hers that she became overconfident and arrogant, often throwing others to the wolves to save her own skin and she lost everyone and everything close to her as a result.
Quinn feels a lot like she's going down the same path and the MC is her Ned Stark; someone to be sacrificed in order for her to keep her secret.
You've stretched way too far in trying to support your Quinn's collapse and MC patsy speculation, comparing MC/Quinn's relationship to Ned/Cersei doesn't work at all. Cersei hated Ned Stark from day 1 of that story, because a) Her husband never loved her because he was hung up on Ned's sister, b) He stared her lover/brother off the throne after arriving from Ruby Ford, c) as Hand he was her direct rival in power, and d) was intending to bring her and her son down with the knowledge that he possessed. In her mind, the Starks were the bane to everything/everyone she cared about.
None of these apply in any way to the Quinn/MC dynamic. In fact, regardless of our feelings towards her, as
michael1984 said, Quinn actually seems to like the MC.
If you follow the story carefully, the person Quinn disdains is actually
Maya, and more importantly, the more MC displays that he likes Maya the more Quinn's dislike grows. Try it. Play a run where MC doesn't display affection for Maya at all - don't defend her during the CUM-petition, don't help her make out with a DIK, don't warn her to talk to Sage instead etc.- and Quinn will actually treat Maya better. This is school playground dynamics in play i.e. If one likes someone, you dislike the person he/she likes because you want him/her to like you instead.
This is also supported by several feedback from other HOTs. Behind the scenes, Quinn seems to be gossiping about the MC like a giddy schoolgirl e.g.
This does not mean that she won't sacrifice the MC if she doesn't have a choice, but it won't be because MC is the target of her hatred or a potent threat ala Ned Stark.
If she had a choice she'd probably take down Maya. Now Maya is not really in a position to be a convincing patsy for her yet (and neither is the MC for that matter), so Riona is in a dangerous position. However, if Maya joins the HOTs but refuses to be on the menu, Quinn may demand that she deliver "mysterious packages" for her instead and then she'd be completely exposed to being hung out to dry (so Maya fans better be careful.)
In any event, whether she will even need a patsy at all is still a matter of pure speculation at this point.