Seems the AFP had their own cameras at Mareeba.
It seems the L/H main gear has relocated itself. The wet wing 402 probably developed a leak at that point, fuel would also flow toward the wing tip (gravity).
Take the fuel cap off the L/H tank on a pretty full aircraft would make a nice water (fuel) fountain, also trying to destroy evidence would be better to open the fuel drains on the other wing & light that too.
Engine fire on take off did cross my mind. Does not seem as much damage to the aircraft that is trying to commit aviation after a 900+m run up at the trees.
A partial power loss (turbo or "popped" induction rubber, mag even) might be reason to abort.
But then how long to unload 500kg with the aircraft on fire?