The Malay Peninsula is not remotely as covered by military radar as India, but I agree that there's some explaining to do in this case. I've flown over both places hundreds of times and there is no comparison. India is on constant alert because of certain neighbours and has a vastly bigger air force.
For which reason also, I find the "Tailgating" theory unpersuasive on balnce to get a silent 772 right over the sub-continent? The Southern route seems more plausible. If 1000 Km West of PER, wouldn't that already be getting tracked by Australian Military eyes? Quite apart from the huge Australian/NSA tracking station up on the Northern Coast of WA?