But there's evidence in ToM that Rand can interact with T'A'R/The Pattern directly from the real world. As for the yelling, it all takes place inside Rand's head.

The main reason I partly subscribe to this theory (I'm far from convinced, but I think it's possible) is that it would be a cop-out for the Creator to get involved to the level of speaking directly to Rand. The whole thing is more meaningful if Rand fights for his own reasons rather than because he's a puppet of the Creator. If we rule out the Creator, there aren't many other entities that could do this.

The only other one I can think of which might make sense is a VERY early manifestation of LTT inside Rand. I don't have the books here with me but I'll reread the part in a couple of weeks and see if that might fit the bill.