The Answers are in Canberra?

We left the underground complex to our repaired plane. Good job James!
Tired, confused and not a little pissed off, we boarded and started the trip back to Canberra.
6 hours later we start our descent to Canberra, after our mandatory stopover in Wilcannia.
The only problem is Canberra isn't there!!
A lake that resembles Lake George and the hills surrounding it can be seen below us but the lake is full and no sign of Canberra.
We manage to contact Sydney tower and they don't know anything about Canberra at all.
We decide to make our way to Sydney to regroup.
As we fly over the city, things are a little different.....
For a start, there is a huge wall surrounding the area just south of the bridge from Walsh Bay, through Wynyard, around to Bennelong Point
Outside this wall to the South there is a lot of activity for a a few miles at which point activity suddenly stops.
Beyond this, the city is like a ghost town.
We decide to make our way to Bankstown Airport and land there. Like the rest of Sydney outside the wall, it seems to be totally deserted here.
Frank found a fuel tanker to refill out plane with while the rest of the party made it's way to the tower. Except for Klaus of course. He is checking out the other planes at the airport.
The tower was empty and looked like it had been left in a hurry. Coffee cups and sandwiches half consunmed.
The newspapers we could find in the tower were all dated around 4th October - the date when the Maralinga blast and Leisl explosion happened......
Frank has refueled the plane and found a truck we can "borrow"
We scrounge up some food, first aid, and spare clothes and prepare to head to the truck when I have to bright idea of trying to call one of my previous colleagues in the city.....