Just like with the 'boyz' version, the directions state that you 'prime' the system at the start of the dive. This makes sure all systems are "go" and gets rid of pesky air bubbles...
Forgive my intrusion, but I have to wonder (on behalf of my wife..) - it appears there's a pocket of air in there, which would compress at depth.
a) Does this cause discomfort via suction as the pressure increases?
b) does this compression pose a risk of breaking the skin seal?
Do you overcome this by filling the empty space with water before the dive, or is it pretty much a non-issue?
Also, once duly relieved, does a portion remain to slosh around in that pocket?