Continuity mistake: As Chloe hurries to put Justin's art book back before Justin comes in there is a piece of white paper sticking out of the top and bottom, based on the way she put it back, of the folder. When Justin sees the folder has been moved there are no papers sticking out.
Continuity mistake: As Justin turns the spike end of the pathway light towards Principal Kwan, in the close up, the light is at a height that is just lined up with the light in front of it. After the shot change, the shot simply zooms out to include Justin on the right side of the screen, the light is now several feet higher than it was before.
Plot hole: Justin's power is telekinesis, which he uses to attack the doctor at the beginning of the episode. He shows that he is targeting the doctor's hands by blacking them out on the drawing, but he has absolutely no way to see what is happening in the elevator to know the exact moment when to drop it and cut them off.