There is another way you can meet the first zombie in the game. First, when Jill reaches the dining hall with Barry, exit out to the main hall without talking to him. Wesker will tell you to go back and investigate.

Jill will automatically enter the dining hall again. Try to exit the door again. Barry will comment on your courage. Walk toward Barry and talk to him. Do not leave the hall and instead to inspect the clock in the room.

The zombie will go through the door and start following you until Barry shoots it. When you go through the door barry was next to, you will find Kenneth with a different body model (more deteriortated).