The curtain on the front door of Laskoff's house rises and falls from shot to shot. Response: There are two different curtains. There is a short curtain on the window on the door. There is a long curtain on the window next to the door. You can see both of the curtains at the same time right after Mr. Lasko says "Let's go."
When Niles and Frasier start to remove the boards from the floor you can see that the boards are clearly not nailed down allowing them to easily remove the boards.
When Frasier is telling Niles about fracture in the skull he says "the temporal bone has been fractured" while pointing at the frontal bone.