The building is locked and you are not allowed to enter because it’s not safe.
There was two guards at the building and after asking nicely a few times they agreed to guide me inside.
Entry was through a vertical ventilation shaft, balancing on floor boards 3 meter above the ground and then climbing down through an empty switchboard. Then we had to find our way through the labyrinth basement using flashlights before we got to the huge conference room.
