I was just looking at the flight plan, IGARI -BITOD is 059*M so the final recorded track was 040* - Winds surely didn't give 19* of drift on the night?
The last location tracked by Flightradar24 is
Time UTC: 17:21:03
Lat: 6.97
Lon: 103.63
Alt: 35000
Speed: 471 knots
Heading: 40
Between 17:19 and 17:20 the aircraft was changing heading from 25 to 40 degrees, which is probably completely according to flight plan as MH370 on both 4 March and 8 March did the same at the same position. Last 2 signals are both showing that the aircraft is heading in direction 40 degrees.
BITOD-BIBAN is 035*M so I presume that ATC gave a shortcut or is this not common practice in that airspace, as it is with European during quieter times? As the final turn at IGARI suggests a route direct given by ATC.
Today there are reports in media that MH370 may have turned around. FR24 have not tracked this. This could have happened if the aircraft suddenly lost altitude as FR24 coverage in that area is limited to about 30000 feet.
So this may explain why there was a 0ft readout from Mode S as anything below 30,000ft wouldn't read correctly due to lack of coverage. Whatever happened, did so before the next data grab at 17:22:ish..