What I liked was that the preview showed two boxcars of people. In the first one, the people had given up. In Rick's they didn't give up, and prepared with whatever they had to fight for their lives.
The first box car contained Garret's group and was prefaced by "THEN", meaning before today. Evidently they had been taken hostage by an equally evil group some time ago and whatever events happened then turned them into what they are today.........