At 4:44 it just looks like they masked off an area and then switch off the mask. Looks fake because it's so good - without actually using it one couldn't tell.
If you meant something else, could you explain it a bit clearer?
Elsewhere in the thread I repeated the experiment on one of the images with resynthesizer GIMP plugin and got very good results too, but not quite as good. Of course I could probably have chosen an image which would have appeared to produce equally good results...