W&F,
You and others promoting the silly "shadowing" idea need to learn about formation. If SQ was minding its own business cruising at M.84 ish and our hero, unaware of SQ's take-off time were 12 minutes off, it would take 1800nm to catch up using Mmo on MH370's T7. You can only "make up" 24 nautical miles an hour, that's the speed differential between normal cruise and Mmo on the T7.