Wow. Good episode. I'm glad the little boy has been saved, but I wish they would find that little girl-- not because I find the storyline boring, but because I'm worried about her. This show is very involving.
I think Shane is fundamentally weak. That's why he got involved with Rick's wife, why he almost shot Rick, why he decided to leave the group and why he shot Otis. He's essentially a good guy. In this situation, his first priority was saving Carl and he was willing to let Otis be the one to get away at first. But when it came right down to it, when the zombies were nipping at their heels, he chose to let the other guy die. Maybe in part because he wanted to be the hero, but mostly because he wanted to live. In a terrifying situation like that, who's to say it's not what any one of us would do? Also, the actor did a great job. He barely said a word once he got back, but his torment was clear-- the other characters read it as horror, but it was clearly guilt.
Aside from that, the episode was full of great moments. The whole thing between Rick and Lori about giving up or going on; the conversation between Glenn and the girl; the latest encounter between Dale and Andrea (I really like Dale-- great character and actor and I completely sympathize with him-- I would have done pretty much what he did); and, of course, Daryl-- he's got a fantastic character arc so far.
And there's got to be more than meets the eye with that farmhouse. Electricity, hot water and no zombies. Where are the zombies? "Did you close the gate when you came in?" There's got to be more than a gate keeping them away.