When Barney removes the metal furnace door it is divided into two sections. When he lays it on the floor it is one solid piece. When he re-installs it on the fake wall it is in two sections again.
The steering wheel on Lord Weston's Rolls Royce is on the left side. The cars in England have the steering wheel on the right side.
Early in the episode, as Paris and Lady Weston go horseback riding, the trees have red and orange leaves and she remarks that autumn is her favorite season. When she and Jim Phelps go to the casino a day or so later, however, the date on the check he writes is "Feb. 14, 1970," which is almost the end of winter in Britain.
Without giving away spoilers, the last scene is an interior shot of four people in a car - two in the front, two in the back seat. Shown from the exterior (on the road), there is no one in the back seat.
As seen early in the show the limo had curtains on the rear window and the rear door windows so you can not see into the limo.
As seen early in the show the limo had curtains on the rear window and the rear door windows so you can not see into the limo.
When the members of the spy ring are listening on the scripted conversations between Marvin Rogers in London and Peter Stone in Washington (whose voice is prerecorded), the recorder is being turned on and off. They should realize at this point that the conversation is a fake.
With flames raging in the furnace, Barney removes the hot metal door with his bare hands without burning himself.