If you are in the elevator and then look to the right, you will see a door that you can reach through the skip where you jump on the "umbrellas" (idk the name) and then jump on the elevated platform with people. If you know a freecam mod or something then just reply!

There is nothing behind that door. Also you can't open it (obviously).

Idk what you are talking about but a "freecam" you could do is type /noclip in the console