As I said Bill I believe squeezing the pellet makes it more dense. Not sure why something has to "leave" the pellet.
I would think if your squeezing something that is soft and pourus anything inside the object (in this case air) would be removed..
I don't discount that possibility, just skeptical.
If anyone has some hydrated pellets perhaps squeezing them under water will tell us if any or much trapped air escapes? That is, one would see air bubbles rising to the surface of the water?