The water filling the basement rises to basement window level, then below, and then equal to, continuously through the scene.
At the end of the episode, Alicia and Charlie return to their last hold out. As they exit the car, both characters are empty handed. The two search the grounds separately when off camera Charlie yells for Alicia. They meet to see an overturned bus on a bridge only now Charlie is carrying Alicia's homemade shiv.
About forty minutes in, when Alicia leaves the photo in a glass jar at the graves, a crew member can be seen walking between the buildings in the background, almost at the center of the frame.