As the terminal ran, Chase turned and slipped out the door just as it was closing. Bough had slowed it down enough to give him time, but hadn't wanted to slow it unnaturally in case some aspect of the Renraku security system monitored how long doors remained open. They knew the system kept track, via ID cards and the door sensors, of which employees went through which doors and how long anyone stayed in a room. Certain sets of matched circumstances would alert the system to a potential security problem.