Shane and Herschel get into a fight in the barn. A forgotten geek bites them both. The others lock them in the barn.
Hahahahahahaha! I like this, speculation about what unlikely scenarios might play out.
I think Rick wakes up and we find out this was all just a bad dream . . . .
or
Carl begins adolescent angst, shoots both of his parents, and begins a Lord of Flies kingdom
or
The zombie virus runs its course and all the walkers die, but not before all the humans die except for Herschel and his step-daughter, who must then procreate to repopulate the earth. Millions of viewers turn off the television in disgust.