As I read this I had to laugh at Rick's group being surprised at hearing they all have some type of zombie virus?? People on this show have been very sloppy in handling their walking dead..
It's something from the comic, dude. It's what Kirkman designed in the writing of the comic that carried over into the show. In fact, the whole "we're all infected" also comes from the comic too, and guess what, it didn't matter if you were covered in zombie blood or not, you still came back. Shane, in the comic, got killed, and he was never shown killing a zombie in the same upclose and splattering method seen in the show.
something i realized just now: rick KNOWS that the dead will turn, if their brains arent destroyed
yet still, he kills shane, and doesnt crush his head. whats the point of that?
Rick in the show, himself, stated he wasn't sure if Jenner was right or not (since he was acting a bit unstable). And before, there was no human killed through another method that allowed for it to occur. So, Rick was never sure until Carl took him out. Not to mention the fact that he had just killed his best friend, a man he knew almost all of his life. If you were in Rick's position, where you've known Shane for years, and you had to kill him, don't you think you'd be emotionally distraught and not be able to think straight at that moment?
Besides, it's different in the comics. The whole CDC thing was never featured in the comics. Shane's death took place much earlier in the comic's timeline (when they were still at the Atlanta camp). It was in
Volume 3: Safety Behind Bars, where Rick found out that they're all infected when two characters who died not by zombie (one from a gunshot wound, the other by strangling) resurrected without being bitten. As a result of this discovery, Rick travelled back to the Atlanta camp, dug Shane half way up and a zombie Shane dug himself up the rest of the way and climbed out of the grave. Rick then shot him in the head, and left him out of the grave.
