Other mistake: The wooden steps in front of the office look to be one plank measuring 3" by 18", but in the collapse under Klink, they appear to be two pieces. Also, Le Beau sawed through the middle support, but neither Schultz or Klink step on it.
Other mistake: After the truck is stopped, Newkirk tosses a dart at the tyre in order to flatten it. Since the tyre hit was the rear tire, there should have been the track from the front tire, but wasn't. Also, a puny, hand-tossed dart couldn't have penetrated the thick construction of a heavy-duty truck tire, let alone flatten it in twenty seconds.
Other mistake: When stopping the truck and Schultz, the area directly behind Carter and LeBeau can be seen to be a matte painting. The reason is because where they are is completely covered in snow, but the open area is very little, and there is a huge snowdrift piled up at the wall.
Other mistake: The truck was stashed behind Hogan's barracks. The Kommandant's office was on the other side of the building. While stealing the boxes of gold, there would be no way that the POWs would have been able to see any approaching figure.
Answer: It's a solitary cell. Steve McQueen, star of 'The Great Escape' is known as the 'Cooler King'.