On the southern side of the station building was the so-called "service entry" ("Diensteingang") for personnel of the Deutsche Reichsbahn (the East German national railways). This entry led through its own control room and then, via several corridors, to a door on the ground floor of the "western" side. The entry was used to infiltrate and exfiltrate agents of the East German intelligence service, and to allow members of the West German communist party and West Berlin socialist party to pass without being checked or recorded. This secret pathway between the two cold war fronts was also the escape route for some members of the West German terror organization Red Army Faction to avoid arrest in West Germany. On 7 July 1976 the officially-wanted Movement 2 June members Inge Viett, Monika Berberich, Gabrielle Rollnick, and Juliane Plambeck escaped following their escape from prison, and on 27 May 1978 Till Meyer, escaped into East Germany via Friedrichstrasse station, though they did not stay there. Viett later escaped to East Germany again and stayed there until the fall of the Berlin Wall. In the opposite direction, on 18 January 1979, the East German double agent Werner Stiller used this path to escape to the West.