Dr Michael Baden of gretatube and OJ fame said she probably rinsed the sodium from her body and then died of cerebral edema.
(Kind of like deaths from heat shock when ya don't take your salt tablets in certain climates and occupations)
Well, that being said, do you know how much water it takes to wash away your sodium? Answer: a whole heck of a lot.
It's mighty hard to die of water toxicity, and you'd NEVER be able to hold your pee long enough to drink that much. Never ever. It's a biological impossibility. You'd need a bladder the size of a beach ball.
So, either she cheated, and peed MANY times, or she didn't drink enough water to become fatally toxic, and the diagnosis is wrong. A stomach will not hold enough water to wash all your sodium away, all at once. It would require several stomach-fulls, and your bladder would not be able to hold that much urine.
The facts as thus far presented, are impossible.