If that phone was in water it would be dead. Strange.
Ah! No, I have an explanation. AIR POCKETS! Unless the plane totally disintegrated, there could be air pockets, in an overhead, etc. Either that or I’d agree with others that it got lost or stolen in Malaysia.
Water + Electricity = Ice.
Except in the case of a cell phone in water. That equals a dead cell phone. Or more accurately, a shorted out battery.
I know someone who accidently dropped their smartphone into a flooded crawl space (about 4 feet of water). Weeks later they went down into it and found the phone. Fired right up. Still worked.