Gnurl doesn't remember ever seeing Zurrik perform this trick before, so when he and Radoon suddenly vanish, Gnurl's eyes get very big, he stops short, and he says, "What the ...."
Gnurl turns back to H'Roosh and says, "Hey, did you know that they could do that?" indicating the vacant space where Radoon and Zurrik formerly were. Then he notes H'Roosh's vacant expression as he gazes up at the tower and says, "Oh. Never mind, sorry, didn't realize you were having that 'tower fantasy' again."
Nothing changes outside, as Zurrik and Radoon materialize inside they find themselves in a large chamber, but it is hard to see as the room is quite dark. They can make out movement in the shadows, but that it all. There is just enough light to indicate that man-sized figures are moving about. They are not immediately attacked.