 CONT: Khan has a warning torpedo fired at the Enterprise. After the  torpedo explodes we see David and Carol Marcus, and McCoy, in the  sickbay reacting to the explosion. Only six seconds pass (of movie  time as well as "real" time) before the turbolift doors open on the  bridge with David as a passenger. In the Directors Edition DVD,  restored footage allowed a longer period of time between Khans  "warning shot" and Davids appearance on the Bridge a moment later.