Quinn should be smart enough to know that's a set up. He's seen the video before, he knows it wasn't for this attack.
I think they'll start the next season sometime in the future with everyone having moved on assuming Brody is dead. Then the season picks up with Carrie either finding evidence that it wasn't Brody and people finding out Brody got away.
It'll be interesting to see if they find out he murdered Walden for Carrie. Seemed like a given with them already asking her how she got away and all, but they could easily over look it in light of everything else.