My thought is that fluids such as atmosphere should be looked at from a spongy point of view where fluids under pressure are going to act more like solids and when decompressed will act more like gas. an easy way of looking at this would be testing the variables of a pool full of hard rubber balls versus a pool full of nerf balls. the results of conditions and movement will be quite different even tho they are made from the same material.
So the big picture is not to judge the whole of the area of any fluid but to give judgement to each area according to its pressure conditions.