The facts from someone who was involved.
The aircraft arrived as QF006 from SIN at 0510 onto the gate after carrying out a normal landing during which only idle thrust reverse was used (due to curfew requirements).
Upon arrival at the gate the crew informed engineers that they had high brake temps in the body gears. The aerobridge was cleared to dock and the ground engineers checked the gear due to high temp report and some smoke from the brakes (which is quite common on this aircraft type). The engineers saw flames from one of the brakes and asked the techies to turn the beacons back on to alert ramp staff to clear the area, and informed crew of fire on brakes. The crew asked for confirmation of fire and groundies replied confirmed and no further communication took place. Obviously the crew initiated an evac as the slides appeared and the passengers deplaned in a totally chaotic manner.
Some slides did not operate simply because the were still disarmed (for the normal arrival) and weren't re-armed before opening the doors. The slide at door 3R did deploy but for reasons yet to be established it deflated a short time after.
The questions that need to be asked here are Why did the crew initiate a total evac without firstly gaining more information from ground crew and why was the evacuation process carried out so badly?
For info, a brake fire on arrival is not a major situation. Generally it is grease, oil and dust that catches fire and can be easily extinguished if it doesnt extinguish itself. I believe in this situation the whole fiasco would have been avoided if the tech crew had asked the groundies if an evac was necessary. Hopefully QF will learn from this and procedures will be changed to enable more input to the crew before they make a rushed un-informed decision.