Who else would have been like that bad guy?
Shutting people out in case they were infected.
Tricking someone else into leaving safety first so the zombies would have something immediate to chow down on.
Pushing conveniently near people into the path of incoming deadites.
Doing whatever it took to survive...even if you didn't.
Sounds like a reasonable course of action in a situation where everyone else is likely to die anyway, and you don't have the burden of a kid or loved one (our hero even advised his kid to look out for Number 1).
When darkness overcomes the heart, Lil' Slugger appears...