You shoot him…
You quickly pull open the door and shoot the man in the head. He immediately falls dead on the front porch.
You slam the door shut and watch through the peephole as the zombies come onto the porch and begin to eat the man.
You go back into the living room to find that the TV no longer has a signal. You’re truly alone.
You hear something scratching at the door and run back to the peephole. The zombies have figured out that you’re in the house. Some are pushing the door and others are pushing against the windows. More zombies are walking toward the house from the street.
Eventually, they’ll get in. You’re sure of it.