"He apparently said stuff like 'oh it's a 24-hour party, we can go in any time'. So he got out of the car, jumped the fence in the darkness, and fell down a cliff."
Stirling said the hitch-hiker got lucky with where he fell.
"If he had fallen the other way, either side, he would have had a significant freefall."
"He decided that he wanted to break the rules, and unfortunately paid the price."
Rescue crews spent three hours searching for the man in the pitch darkness, and were just about to call off the search when they found him in a rock chute.
Stirling said they'd already moved the festival from a previous site, in order to have it at a more secure place.
He said this incident would mean they'd need to increase security again, possibly with 24-hours measures.
Fire and Emergency central shift communications manager Carlos Dempsey described the overnight rescue operation as "dramatic and difficult".
A Palmerston North Rescue Helicopter spokeswoman said crews could hear the man but not see him through much of "incredibly intense" three-hour rescue mission.
Dempsey said Hunterville and Kimbolton fire crews and the rescue helicopter spent three hours in pitch darkness to find and reach the injured man who was trapped about 70m down the sheer cliff face.
The helicopter was eventually able to winch the stricken man out of danger, Dempsey said.
"Access was quite difficult," he said.
The helicopter spokeswoman said the fire service forded the river to pinpoint the man's location and climb up to him.
When this was unsuccessful because of the nature of the terrain, they used a spotlight to find him.
"Shining a spotlight in his direction and getting him to call out allowed his general position to be located."
But even having a general position, the rescue helicopter struggled to find the injured man in thedense bush and trees.
The search was about to be called off when the man was finally spotted in a rock chute.
The helicopter winched a paramedic to the man to stabilise him and pulled him to safety about 20 minutes later. After paramedics provided further treatment at the nearby Reserve, he was flown to Palmerston North Hospital with critical injuries.
A St John spokeswoman said the man was still in a critical condition in hospital today.