 The original concept of the series was that each episode took place  in real time. A timer on the corner of the screen counted down from  22 minutes, pausing in the middle for one commercial break. The  timer was discontinued after a few episodes. For the second season,  the conceit was abandoned altogether in favor of a more conventional  time structure, perhaps due to a combination of network pressure and  the difficulties in planning and filming the action so that it  appears to unfold in real time.