As a whole I actually enjoyed this episode but I agree with Squid, the scene with Rick banishing Carol didn't feel right somehow. I know why he did it and I agree with his decision but the scene felt rushed and I think that it lost some of it's punch with the introduction of Sam and Ana who added an unnecessary element of humor to the moment.
Aside from that, my only other real complaint about the episode was Lizzie. Good God, I will be shocked it that girl doesn't get herself and several other people killed within the next few episodes. If I didn't know any better, I would swear that she was Andrea all over again.