As mentioned multiple times by now, we did not expect anything but strange, moving shapes. The mind, to anyone who has spent much of their lives researching it, seems too complex to function like the slightly surreal, internal worlds seen in so many cartoons and similar fictional representations of it. The mind should be a place where thoughts are not tethered by what our eyes are used to seeing. It should be a place of almost random, feverish chaos - only decipherable with years of study and work.
Instead, we get a humanoid that seems to imply, rather clearly, that our presence is known and unwanted. I suppose its knowledge of us isn't too amazing. The subject had a very good idea as to what we were doing, of course. It's the way it chose to display itself. It seemed to be blocking us off from even greater secrets that lie further into the seemingly infinite area behind it.
Keep in mind that the machine was not made to function like a camera. We imagined its position staying stationary. Instead, the subconscious moves itself in a way that appears the machine's reader is acting like some sort of camera. It, the figure and the landscape, move toward us, though we are the ones who seem to be moving. Why did it choose such a strange way of moving itself?
One specialist proposed that by creating the illusion of us approaching it, it emphasized our perceived intrusion. It was standing guard. We approached it. It blocked us. Well, so it would seem.