When House begins the heart biopsy, the room blinds are open and Ian's parents can be seen peering into the isolation room. In fact, Chase offers to close the blinds but House says, "No, let them watch. I do my best work on the big stage." When Ian goes into cardiac arrest we can see that the blinds are now closed; however, the parents can be seen behind the blinds. Next we see the hospital staff respond to the code blue. As the staff run towards the patient's room, Ian's parents appear across the hall and are now stepping towards their son's room in response to the commotion.
the teacher tells her class that blood returning to the heart is a "deep purple" this is in fact wrong the blood appears a darker red. Your veins only appear to flow with purple blood because of how your skin absorbs and reflects light.