back in 2002 I nearly died from water intoxication, also known as hyponatremia. At the time I had diabetes insipidus, which made me very thirsty. I was so thirsty that I binged on non stop glasses of water all day for over 8 hours uninterrupted. Then, at nightfall, I threw up, in much the same way a drunk throws up after having too much alcohol. I got to the hospital just in time to be connected to a saline IV -- had it been just a few minutes later I would have died.
All that water flushes the sodium out of your body, to very low and dangerous levels. That's what happened to me and sounds like that's what happened to this woman trying to get a Nintendo.