What's bizarre is that if the plane did turn around, why wasn't there an attempt to communicate this decision?

And if it did turn around and experienced some kind of failure that disabled comms and caused pax and cabin crew to lose consciousness, is it possible that it simply continued to fly until it ran out of fuel? And since there was plenty of fuel on board, is it possible that it might have even headed towards Africa? I am only asking because searching for it in the current area when in actual fact it might have crashed in the Indian Ocean would be disastrous.