This is supposedly being set in an Eastern block country. When the team first exit the truck and let down the ramps, there is an American flag flying in the background horizon.
At 21 minutes in: When three SS officers are at the desk in a far shot, the map on the wall behind the officer on the phone is of western Japan.
The wording "Emmett Drugs" is visible as the military police pass by when converging on the warehouse. Not a very likely business name in an eastern bloc country.
It would have taken several months and a team of construction workers to build and equip the fake submarine, yet it was all accomplished in about a day. No one, not even a movie studio, would have had such a set just lying around.
When the Colonel says the car with the escapees is travelling at a speed, he calculates they are travelling in MPH. In Europe they would calculate in kilometers per hour.
In the final scenes, Phelps and Paris escaping through an "emergency airlock" should at least have wet hair when facing Col. Sardner just a moment later. That might have brought unwanted attention from such a perceptive man as Sardner. While theoretically possible to dry a body and get into uniform in about a minute, it would be rather impossible to dry and comb such hair as Phelps' or Paris' in a such a short time.