Two things that, I think, would have made this a better episode:
One: Lizzie puts down Judith instead of Mika. That way you'd still have Mika around to plead for her sister's life when her sister was clearly incapable of doing so. I mean, it's one thing to put down the psychopath, even if it is a kid, but how much harder would it have been with Mika making the case that "she's still alive, maybe she can change, maybe we can watch her to make sure it doesn't happen again.." This would have also lead to a much more tension when the group inevitably meets up with Rick et al.. do they tell what really happened to Judith? And if they do, what happens then?
Two: Tyreese follows through on the logical conclusion when he learns how Carol betrayed him. It wasn't 10 minutes before that that he was talking to Carol about how he knew and trusted everyone around him, and didn't want to live in a place where he couldn't. Having it then turn out that not only was Lizzie a psycho, but Carol was the one who took out the two at the prison should have driven it home to him that there is literally no place on earth where he could trust everyone around him. So it would have been completely logical, understandable, but at the same time surprising to the audience if he'd instead taken his own life there. This would have left Carol with Judith, so again, it would have been no easy out for Rick when they finally meet up -- does he stick to his guns of thinking of her as untrustworthy, or does he relent? As it is now though, the path to Rick forgiving Carol has been made simple by Tyreese doing so, as he was the one most wronged by Carol, so how can Rick in good conscience not forgive her. Too easy.
