finally had a chance to watch this. i dont know. i still feel like the infection whatever it is, changes you mentally/behaviorly, before you die and turn into a full fledged walker. It seemed pretty obvious with Shane, now Rick.
what im focusing on is the breathing. you have to pay attention to it. Dale's was breathing almost like a walker right before he died. when shane was in the shed with randall (or maybe another time, but def a time when he was alone with randall) but his breathing sounded ALMOST like a walker. not like full on growling like zombies, but i keep thinking they put the audio of them breathing loudly like that for a reason. they did the same thing with Rick right after he told Lory about killing Shane. Something tells me theres more to it. maybe its just foreshadowing, maybe its something else, but im trying to read between the lines and pay attention to small details that may become important later.
just my .02. looking forward to the fall for season 3!