Although something is VERY likely to have happened...
Palangkaraya is 2100m...
If we assume a TOW of 48-49 tons, it'll give flap 5 V speeds of:
V1 135, Vr 137, V2 143...
6 seconds in the air at V2 = 441 meters
Stopping distance at Max man Brakes at 140Kts = 850m
So, it took off and became airborne at...
2100-441-850 = 809 meters?
How likely is that?
And that didn't take into account vertical displacements and inherrent lateral displacements caused by making those 180 turns on the runway ends.
If its 6 secs after brake release, then that's a different story...
Sometimes pax witness statements just make me wonder...
PK-KAR