Know something about outback logistics, do you?
Quite a lot.
The Searey owner will be holed up at the nearby Best Western Motor Inn or Hilton, waiting for the lake to fill up. He's probably grabbed a hose and run that across to the lake, to help it fill more quickly.
Once the lake's a foot or so deep - that might take up to a couple of days - he can hitch a ride on a local ski boat or tinnie to get back to the aircraft. He could even buy an inflatable 'lilo' and paddle himself out.
Then he just water taxis to the local marina, tops off the tanks, picks up his gear from the hotel, and off he goes.
The logistics seem simple enough to me.
What more, exactly, are you expecting someone to know and post in this thread, that hasn't been posted already?