Chris Goodfellow at Autopia, Wired's Aviation blog, writes:
Fire in an aircraft demands one thing: Get the machine on the ground as soon as possible. There are two well-remembered experiences in my memory. The AirCanada DC9 which landed, I believe, in Columbus, Ohio in the 1980s. That pilot delayed descent and bypassed several airports. He didn’t instinctively know the closest airports. He got it on the ground eventually, but lost 30-odd souls. The 1998 crash of Swissair DC-10 off Nova Scotia was another example of heroic pilots. They were 15 minutes out of Halifax but the fire overcame them and they had to ditch in the ocean. They simply ran out of time. That fire incidentally started when the aircraft was about an hour out of Kennedy. Guess what? The transponders and communications were shut off as they pulled the busses.
Get on Google Earth and type in Pulau Langkawi and then look at it in relation to the radar track heading. Two plus two equals four. For me, that is the simple explanation why it turned and headed in that direction. Smart pilot. He just didn’t have the time.
Read his entire piece (which I don't want to quote all of here). This is the most calm, logical, and reasoned answer I've seen yet. Don't tell CNN though, they are having fun with their on-air circus.