The key to what was happening with Carrie was presented well before the appearance of Brody - played by Damian Lewis. When Carrie is running through the hospital, she's accosted by Quinn, whom Carrie beats down. First, in her condition, there's no way Carrie would've gotten the better of Quinn so easily. Second, what was Quinn doing in the hospital? Third, Carrie's bettering of Quinn in combat is a manifestation of how she feels about Quinn: she thinks/knows she's better than him, even though she's somewhat attracted to him, and a part of her would like to beat him out of her life.
Because, as the Brody scene makes clear, she still loves Brody. Note that this Brody - as my wife immediately noticed - was not quite like the Brody we knew. He was much calmer, in control, and even nurturing of Carrie. Because, that's just want Carrie wanted.
Meanwhile, this whole thread finally dealt with the elephant in the room throughout this whole season so far. Not only has Carrie not really gotten over Brody, but her dependence on drugs makes her vulnerable to what her Pakistani/terrorist counterpart did to her. The good news is that, once Carrie gets through this, she may be at last over Brody. Seeing his manifestation may be part of her getting him out of her system. But she'll never lose her dependance on drugs.
The other excellent thread in this episode is Saul and Haqqani. That conversation at the table is priceless. Saul critiques Islam. Haqqani responds with an apt critique of Christianity. Saul replies: I'm Jewish. And Haqqani has no answer.
This season of Homeland is really something - which means, in some ways I'm enjoying it more than the first three.
And see also Homeland on Showtime ... Homeland 1.8: Surprises ... Homeland Concludes First Season: Exceptional
different kind of espionage