D7237 turn-back
FR24 shows that the aircraft had started a turn-back to Perth less than 3 minutes after the big bang. For what it's worth, it also shows one of the first things to happen was a sharp climb of > 800 ft before commencing a swift descent, initially to 24,000 ft. No doubt they were pretty busy during the first several minutes.
So now lets throw in some politically incorrect conjecture.
Having made the decision to return to Perth and committed to that path, the cultural reluctance to reverse that decision took over.
Once the aircraft was pointed at Perth, that's where it was going, no matter what.
Conjecture? Absolutely, but not out of the realms of possibility.