@IanW;- The fire theory isn't 'baseless'. It's based on a known, T7-specific issue. Everything about this incident is unprecedented, but this is one area where at least one of the theories is grounded in
some known facts. Added to this, a current T7 driver has explained how he can see a chain of events that fit few facts known thus far. No Martians required.
Could there have been some mischief on-board? Of course, but for all the well-rehearsed reason chewed-over ad nauseam already on here, it doesn't seem likely. a/c have disappeared because of technical issues before. They haven't, as far as I'm aware, disappeared because a terrorist wanted to 'hide' a crash. They generally like to go out with a bang.
@RifRaf3;- No, it's not my 'Pet theory', nor even my theory. I'm just pointing out that it has some basis in reality, rather than just being based on nothing more than speculation....