The Walking Dead has really taken an upward turn this season. Personally, I think it's the best the series has ever been, and it just keeps getting better. This episode had two great callbacks to episodes way back in Season 2.
Back in "Chupacabra" (episode 5, Season 2) we saw the city of Atlanta being napalm bombed by military aircrafts while the gang watched on.
The after effects of the bombing were finally revealed when Beth and Dr. Edwards stood on the rooftop of the hospital and the city lay before them, completely destroyed.
The second Season 2 reference came when Officer Dawn grabbed Beth's wrists and revealed her scars after talking to her about working off her debt to the hospital. This was the first time since Season 2 we've really seen Beth's suicide attempt mentioned, but I'm glad to see the writers hadn't forgotten about it - it really does show how far Beth has come over the last four seasons.
It'll be interesting to see if there are any more callbacks to former seasons in upcoming episodes.