I think the phrase ", say #3," confuses people. Taking it out removes the ambiguity: "[The] host, who knows what’s behind the doors, opens another door which

I think the phrase ", say #3," confuses people. Taking it out removes the ambiguity: "[The] host, who knows what’s behind the doors, opens another door which [...] has a goat." So he always shows a goat. If he opened the door with the car then the game would be ruined.