Unfortunatly that isn't what actually happens.
What happens depends on ph and the amount of dilution and impurities in the water. Your stomach is not a swimming pool. Also hypochlorous acid is a strong unselective and potentially damaging oxidizer. It is not the same as chlorine dioxide. Chlorine is produced and only some of it turns into HOCl, the rest offgasses or reacts with the stomach contents to produce harmful byproducts