This one occured from about the time I arrived in Sydney in it’s current form. Though the emtpy room existed for some time before.
I am in the top of a dome shaped room looking down. Two people, possibly male stand and look at a device. It is like a winch, with wooden handles and a large metal chain. The chain goes through a hole in the floor. It is locked. They are checking that it is still locked and that it has not moved. They exit out onto a metal foot bridge through a metal door which slides shut downwards.