The scene with T-Dog is what left me confused about what attracts the zombies. In the first season the reason for Rick and Glenn covering themselves with zombie guts was to remain undetected by the zombies because of the human smell attracted them. Then, in that same scene, when the rain came and the zombie guts washed off them, the zombies went all feeding frenzy.
That is why when T-Dog got the blood waterfall coming from that gash on his arm, I was sure the zombies would have stopped and ran for him. Even though a dead zombie was thrown on him and he lay still on the ground, I would think the zombies could have noticed the smell of the blood.
I would also like to comment on the herd in that episode. They were walking all unstable, almost dragging their feet, yet later on, there are zombies running through the woods like crazed men. The episode last night had zombies running around the outside of the hospital. Are there degrees of disability that comes with how long one has been a zombie?
Also, they seemed sensitive to sound, even the smallest noise, such as when Andrea was in the camper bathroom last episode and tinkered with the gun parts. Yet, last night in the scene at the hospital, Shane and that guy who shot Carl (can't remember his name) were hiding behind that car and then opened the creeking door, made a loud noise as the trunk opened, and no zombies noticed. Either I am not understanding what attracts the zombies, or there is a rash of inconsistencies.