Water Pressure At 10 meters - The Bottle Experiment

At 10 meters there is still the same amount of air in the bottle as there is at the surface, but the air is compressed under pressure.
The same happens to our bodies. As divers we wear drysuits to keep us dry and warm under water. As we descend the the air inside the drysuit compresses, vacuum packing the diver. We must add air as we descend to avoid the vacuum.
The deeper we descend, the quicker we use our air in our cylinders. Just like the bottle there is still the same amount of air in our cylinder, but its compressed.