Sentence:  And his final act—leaving the Watch to accompany Tormund and the Wildlings back into the woods North of the wall—no longer seems like a <WSD>dereliction</WSD> of duty. It's the recovery of duty, found by a man who feels he betrayed his queen, who thinks there's no longer a place for him in these lands. 
Meaning of the word marked with <WSD> tags:  Willful neglect of one's duty.