If 2 holes work I'm guessing the third will toot too. Fake news!
@Wingnut Thats what I was gonna say at first but after some consideration its probably true.
Water doesn't compress, so thats why you can pee at depth. The increased water pressure will compress your bladder and if its not empty well then you have to pee because the pee doesn't compress. Stomachs usually aren't an issue for some reason. I've puked a lot at the surface but only once at depth. That was most likely due to oxygen toxicity where the the 36% oxygen mix I was using caused my body to react. By the numbers 107ft was the max depth for that mix but vomiting is one of the symptoms of breathing too high of a concentration of oxygen at pressure. Another symptom is falling unconscious and drowning so I got the better symptom.
BUT...the gas, any gas really will condense at pressure. With air its volume is reduced by 1/3 for every 33 feet of depth due to the water pressure. The gas in the tank doesn't compress because its protected by the tank but once it enters the regulator hoses it condenses. So you're breathing a greater concentration of air with each breath. This is why oxygen becomes toxic at higher pressures.
So the gas in your gut compresses. Note this also happens to the air in your lungs and in your bloodstream. So the pressure forces any gas in your body into the surrounding tissue as you go deeper. As you rise to the surface the gas will come out of solution and expand. Thats what causes the bends, when nitrogen from the air we breath comes out of solution and makes bubbles in our bodies. Same thing occurs when you shake a soda and then open it.
So the gas inside our gut is probably forced into the other stuff in our gut with pressure but it will come out as the pressure decreases. Regardless the volume of the gas is reduced by 1/3 at 33ft so you probably wouldn't feel the need. Besides most divers do not have a big bowl of cabbage before diving. They save that for after the dive.