The Tri State Area Subsystem is the first state-of-the-art secret system that is placed lower than any other public services like sewers and subways. It was located from -500 to -1000 feet below ground. In the Subsystem, vast network of tunnels interconnecting the city, with full light and air supply, provides support for secret services and escape paths. It was rumoured that the Subsystem never had an entrance. And that was quite right. The only way in is a SYSTEM Card (SubsYStem TEleportation Module Card), which is only given to people with high level of trust. These cards can only be used in an isolated place away from anywhere and any kind of interaction between two humans. For example, teleportation can only be activated in elevators, lavatories, rooms and any other enclosed space like a safe box. Only several people (e.g. The President) can use this card anywhere they wanted.
To be continued...