typing sequence (Jessica firing a fake gun for a class and  someone pushing Jessica, in silhouette, down a flight of stairs);  and the closing credits are run slightly differently: there is a  break between each credit card (the series virtually always jumped  from one card to another with no breaks). There are also fewer guest  stars (seven) on this show than on any other, with several bit  players not credited at all (the old society lady killed at the  beginning, two Chinese nuns and several classroom students have  speaking parts but arent listed).