Sentence:  It's an episode of characters returning to their own pasts as different people. They can retrench like Cersei, back on her bullshit, I mean, warpath. Or they can adapt, like The Hound. Neither way necessarily ensures success, but we know the archmaester isn't unequivocally right. We've seen dragons reborn and armies of the <WSD>undead</WSD>. I wouldn't be so sure that Wall will stand forever. 
Meaning of the word marked with <WSD> tags:  Those creatures which are undead; that is, dead yet still animate.