House's office is on the fourth floor of the hospital which, according to the directory by the elevator is the top floor. In addition, the elevator call buttons on the fourth floor only have a 'down' button available. However, multiple shots within the elevator show 7 floors.
Multiple times throughout the series, the doctors claim that a particular patient is unable to have an MRI because he/she has titanium screws, rods or plates in their bodies. Titanium is non-magnetic and patients with titanium implants can be safely examined using an MRI. Issues would only arise if the titanium were installed using fasteners with magnetic properties.
Though this is probably intentional, to create a more visually striking scene, the show quite literally never correctly depicts the proper treatment for a flatline. Flatlines are treated with medication and cardiopulmonary resuscitation (CPR), not a defibrillator. Defibrillators are used to correct irregular heart rhythm (fibrillation) -- not the complete absence of one.
In some episodes, doctors are seen restraining a patient during a seizure. Patients having a seizure should never be restrained, as doing so can cause more harm.
With, very, very few exceptions, characters in the series don't wear eye protection when performing surgery. It is standard practice throughout hospitals in the United States to do so. However, this was a deliberate decision made by the director for theatrical reasons.