I'll assume that Baromir always knew how to play the piano, it just hadn't come up yet.  :-)<br/><br/>As for ventilation ducts, unfortunately the security corridor is completely cut off from the ventilation system, and has its own heavily armored life support system completely separate from the one inside the vault.  (so that intruders can't infiltrate the ducts or use gas grenades to knock any defenders unconscious)  The vault is meant to serve as the last line of defense for the station, in the event of a major boarding action.