No segundo episódio da temporada 3 ...
when Rick and crew are making their way through the prison and killing walkers, they encounter several riot gear covered zombies who have to be killed by lifting their visors and stabbing them under the chin. If these guys were wearing armor, they obviously didn't die from being bitten. They didn't shoot themselves, and they (presumably) didn't starve, since there was food in the prison and outside. Why are they dead?