Citizen Kane Plot holes

Super Plot hole: When Charles Foster Kane says ''Rosebud'' in his bed before dying; there is no one to hear him. His maiden actually enters the room a couple of seconds after his death. No one heard him say ''Rosebud'' and there is thus no reason for any reporter to search any meaning for a word no one heard. Even if the plot hole could have been easily corrected, it does not change the fact that the movie's premise does not work as it is.