I'm curious what more you think you learned about Quinn and Rio's dynamic from this episode that wasn't clear before. It's been clear since season 1 that Quinn manipulated her and used her. If anything, the new information we got this episode was confirmation that Quinn actually did care about Riona, despite her own best efforts not to.
To put it simply, he tells us that she could have had a life outside of crime, but she chose to hang out with her father's drug dealing “friends”, I used to think that (ok Quinn is like that because she doesn't know any other way of life and has had to adapt, and I can sympathize with that) well no, turns out she's into all that of her own free will and that's what pisses me off.
And as for Riona she turned her into a self destructive victim life, because she confesses to us that she actively seeks to take her away from her because she can't tolerate having someone good with her and instead of telling her “stay away from me because you'll have a bad time” she prefers to put her on edge because she's too selfish, and the fact that she cares deep down doesn't take away that she's fucked up and will surely splash the shit on us soon too.