The tow bar was disconnected and left in front of the aircraft, both groundcrew thinking the other had secured it to the tug.
The aircraft then taxied from stand 9 for about 100 metres before grinding to a halt, disembarking the passengers and having the fire crews do their bit.
Now whether the short cuts were taken by the flight deck remains to be seen. If they taxied too early, didnt wait for signals etc, that is pure conjecture. But I'd of thought that as soon as you move such a hefty bit of kit would be immediately noticed. It must of needed a fistful of power!!!!