1) Immediately when you get to the Dining Room at the beginning of the game, exit back to the main hall, and Wesker will say "Investigate if you hear any gunfire", and you'll go back to the dining room.

2) Once in the Dining Room, try to exit again, and this time Barry will say "Lost your courage already? It's not like you!", and you won't be able to exit again.

3) Now go talk to Barry as you normally would.

4) After talking to Barry, head to the grandfather clock and before you can get near it, a zombie will come out of a door and chase after you, Barry will say a pretty ridiculous line, and then reduce its head to a gory pool of blood and brain chunks.

5) After this hilarious sequence, you'll have to go report it to Wesker back in the main hall, but unfortunately, he's gone.

6) Go around the back of the stairs looking for Wesker and when you come out the other side, Barry will talk to you a bit and give you the lockpick.

7) After Barry leaves, go back to the Dining Room, and in through the door the zombie came out of, turn left, then right and you found your old buddie's (Kenneth's) mutilated body, only this time more mutilated, without his legs (or ammunition clips), which will confirm that the code worked.