The officers count the inmates and say there's 10 missing. There are indeed 10 inmates hiding in the pool. However, Pennsatucky and Chang had escaped the prison. The officers counted Linda as an inmate, who had been hiding in Litchfield the whole season, and wasn't on the list. That would make it 11 people missing, not 10.
In the flashback scene when Gloria is being arrested outside her store, there is a cardboard cut out of Andrew McCarthy, who is an actor from the 80's (Mannequin, Weekend at Bernie's, etc) and also directs a few episodes.