I really liked this episode. It was easy to predict after watching how the first episode ended what was gonna happen next but that doesn't mean it was bad. They've got some real problems now with whatever this disease is that's infecting people.
It maybe one of the kids feeding the zombies. I think all those half eaten dead rats lying around may very well be responsible for the illness that's spreading in the prison. Rats carry all sorts of disease and leaving the dead ones there is not a good thing. It will probably turn out that one of the kids was trying to be nice to the zombies by feeding them but unintentionally put the whole group in danger by allowing the disease to spread by not getting rid of the rat remains.
Now the other big issue is who burnt the bodies of those two people? It looks like they may have gotten sick and died because of the trail of blood that lead to them sure made it seem that way. One of them I think was the chick that Tyreese was getting with. At least her death will toughen him up which his character needs.