Making the First Move
On June 11th, at 1:03 am, the convicts decided to move. They each crawled through their respective holes, up through the ventilation shaft and onto the roof of the prison. The reason we know this is because they made a loud noise when removing the ventilation grate that alerted the attention of some prisoners.
Keeping Their Heads in the Game
Fortunately for the escapees, the guards didn't hear the bang from the grate on the roof. In fact, they had just completed a patrol and had nothing to report. The paper mache heads kept the convicts' escape a secret until the next morning...