As commented on the by now closed note: https://www.openstreetmap.org/note/3322846

West to the 3 elevators, there is a staircase leading all the way from 1. OG to 6. UG. (the staircase goes one further down than the elevator. I assume so at least, as the assumend level "6. UG" (=basemt) is not accesible to the public. The staircase is located east to the elevators from 4. UG to 6. UG


entry zone and staircase EG. Viewed from roughly west. Staircase west of elevators.
https://pictshare.net/f203xw.jpg

Staircase and elevators at 5. UG. Viewed from roughly west:
https://pictshare.net/stmj92.jpg

Staircase at 5. UG. Staircase east of the elevators:
https://pictshare.net/1xqbid.jpg

Staircase switches from west to east on 4. UG (coming down). the path from one staircase to the other goes through the entry zone of the elevators

elevators at 5. UG:
https://pictshare.net/sqbih2.jpg

via StreetComplete 45.2