No, literally, he didn't have all the faculties at his disposal. The place was on some kind of automatic quarantine lockdown so he didn't have access to..
..yeah, okay, he'd lost all hope and maybe his marbles too.
I suspect there's a difference between the airborne version of the virus that I think everyone is infected with and the kind of rapidly lethal sespsis that people die from by getting bitten or severely clawed by a zombie. Also, someone else pointed out that when Rick was trying to show Shane to bait the chain link fence with his own blood, that Shane used his knofe on a zombie, then sliced himself to bait the door of the school/prison bus without being noticeably affected so I kind of think that if you die from any means short of heavy head trauma in the first place that you're going to rise and that zombie contact itself isn't enough but the sepsis can be deadly in and of itself.