A vent on the inside of a closet is gonna look a bit suspect! And where would you find a vent for a 3" hole that you cut in a closet? Even plastering looks odd inside a closet..

And if your talking about venting from outside through a brick wall into a closet thats even more dodgy! How are you supposed to get away with drilling through a brick wall in an apartment block? Certainly not practical for me and im sure its not for many others too!