WON’T THE DISSOLVED HYDROGEN GAS IMMEDIATELY ESCAPE OUT OF THE WATER?

Yes, it does immediately start coming out of the water, but it doesn’t just vanish immediately. Depending on the surface area, agitation, temperature, etc., the hydrogen gas can stay in the water for a few hours or longer before it drops below a therapeutic level. This is much like carbonated water or soda that contains carbon dioxide gas (CO2), but because it does leave, it is best to drink the water promptly before it goes “flat”.