Asking because throughout my life (including when I was little) I’ve eaten cups full of raw pasta (the rice shaped little pasta) almost like it was a drink. I finished a 500g packet of wholewheat dry spaghetti just the other day. This is something I actually do so often I got told off by my dentist last year because it’s wearing my teeth down.
I think this is the right explanation, assuming the story is true. Dry noodles expand when put in hot water, and I would think that includes gastric acids in the human body. The boy started having symptoms in half an hour and died soon after. That’s too fast for something like food poisoning, and they didn’t find anything wrong with the noodles being sold. So it sounds like pressure buildup from them expanding inside him caused damage.
OP, I would be careful not to eat too much at once, and eat slowly. The boy ate three packets at once. Maybe eat some other stuff with it so the noodles can’t build up a large mass of just noodles.
I remember reading this is actually a myth and comes from the idea that birds will explode if you feed them rice. The volume stays the same because the water ends up going into the rice.