[youtube]http://www.youtube.com/watch?v=q5w6ieaTxGA[/youtube] Love the videos this guy does, this one is fairly lengthy but well worth watching - very interesting theory.
I could only say "wow." when that grill theory came up, but then I also remembered that when we tried taking the cube into the elevator, it was destroyed and nothing "human" or no noises like that little scream came out of it? That got me questioning now...
You can't take it into the elevator, because Glados remotely destroys it, which is where the scream sounds comes in. Edit: Can't take it in even
Aah now that makes things clear and sense. Although I think I heard such a scream at some other place in the game... Gotta play it again this summer to remember it all!
If I remember correctly glados was talking at the same time so it might have been hard to hear the scream.