If England declare overnight, barring weather, the draw is out of the question. If Australia bat for the 2 days they will be well past the 500 mark. Its very easy to accumulate quick runs here with this outfield. If its sunny we are a small chance, if its overcast its game over.
If england bat the first session and get 600+, Australia should defensively try and draw the game. People can go on about you have to be positive, ... thats garbage, look what happened in India last year, 2nd test, just to name one example. Then compare that to say England in the 1st test, or the 1st test of England/Safrica last year when South africa stonewalled for 2 and a half days to get the draw.