-- You're the bad guy. The a/c is at TOC, so it's time to get to work hiding.
-- After the TOC message is sent, shut down ACARS first, since you're still in Malaysian ATC radar coverage.
-- A few minutes later, once the handoff to Vietnam's ATC is attempted by Malaysian ATC, you go further dark by turning off the transponder(s).
-- You're now invisible to ATC secondary radar, the handoff was never completed, and you've bought yourself some extra time since neither Malaysia nor Vietnam can see the a/c (except for a primary target).
-- Do whatever voodoo it is you need to do.
Imo, this is a genius strategic planning!