Revealing mistake: As Burkhalter's car comes into the camp, it's easy to see that it's a re-use of stock footage.
Is There a Doctor in the House? - S3-E18
Revealing mistake: As Carter blows into the bottom of the oven, the suds that hit Newkirk in the face come out in a thin stream on top, not out of the whole stovepipe.
Revealing mistake: As the camera looks at Schultz driving the car, even though he's moving in the seat, you can see through the back glass the car isn't moving at all.
Clearance Sale at the Black Market - S4-E1
Revealing mistake: After Kiegel shoots out the bulb the light takes a couple of extra seconds to fade out.
Revealing mistake: The film is flipped as the swastikas on the Gestapo uniforms of Hogan's men are reversed.
Revealing mistake: The first shot of the train the view is normal. Then after Lebeau starts in reverse you can see the smoke trail going in the wrong direction. The final shot shows the train moving in reverse, but notice the smoke trail is going to the rear of the train instead of the front as it should be, since it's moving in reverse. (00:15:05 - 00:22:25)
Revealing mistake: When the homing bomb hits Burkhalter's car because Klink used the radio, you can see the mini tank from "Tanks for the Memory" (s2e9) sticking out of the wreckage.
An Evening of Generals - S3-E13
Revealing mistake: The silver rack with bowls starts moving a second before the rocking explosion.
Revealing mistake: LeBeau hands Schultz the pan straight from the hot plate, but Schultz puts at least three fingers around it while eating without any apparent issues. Note that LeBeau earlier said the Crepe Suzette were "not quite ready yet" - or in other words, still cooking. (00:01:40)
Revealing mistake: After the cell door blows, you can see the fuse of the stick of "dynamite" Newkirk placed still burning on the ground. Since the dynamite would blow when the fuse is burnt up, that literally can't happen. (00:22:40)
Revealing mistake: As Hogan goes through the hole to the ladder, the "rock" he brushes against flexes for a second. Likewise, when Kinch climbs through, the "rock" under his hand flexes and mashes down as his weight is on it.
Everybody Loves a Snowman - S3-E14
Revealing mistake: When Hochstetter goes to open the snowman, you can see the plug is a poorly disguised piece of wood, as well as the piece of metal around the opening in the snowman.
Revealing mistake: As the scene opens, the camera starts on a shot of the guard tower's roof. As it pans left and down into the yard, over the hill on the left side of the shot you can see a modern crane structure and the corner of a building in the distance.
Funny Thing Happened on the Way to London - S3-E5
Revealing mistake: When the staff car enters the camp, you see a set of tire tracks leading up to, and stopping at, Klink's position. When the car comes in, it precisely follows the tracks, suggesting previous takes.
Heil Klink - S2-E22
Revealing mistake: After Browner gets out of the staff car and is going inside, as the camera pans to the left following him, you see the Desilu Studios water tower.
Revealing mistake: When the boys are working on the fence, when the camera is on Hogan, you can see a modern metal building in the distance.
Revealing mistake: At the end, when the boys are in formation and Klink is walking through the ranks, he walks around Hogan's right side. As he does so, you can see LA's Desilu water tower.
Revealing mistake: When the High Command men are watching the "noiseless engine" plane, the camera cuts to a shot of the four of them in the car. To the right (camera's left) of the man in the right side, back seat, you can see LA's Desilu water tower.
Revealing mistake: While talking about Von Baler's daughter, Hogan is facing the building talking with Carter and Newkirk. Behind him is an open area of the camp. If you look, you can see that there is no guard in The Tower, no shadow of The Tower of the guard hut (the sun is behind them and Hogan), and the snow is piled up about three feet behind Hogan, suggesting that the background is a wall mural in the studio.
Clearance Sale at the Black Market - S4-E1
Revealing mistake: The Major goes to shoot out the light that the boys have turned on so Kinch can get the pictures. The first shot is angled too low to hit the bulb, but there is no impact on the front of the door's crosspiece; the smoke and dust comes from behind it. The second shot gets the bulb, but there is no muzzle flash, just sound. Also, there is no impact mark on the brick wall behind the bulb.
Answer: It's a solitary cell. Steve McQueen, star of 'The Great Escape' is known as the 'Cooler King'.