"escape From Iran: The Canadian Caper," a CBS movie at 8 tomorrow night on Channel 9, amounts to a well-deserved and well-executed bow-taking on the part of Canada for its efforts in freeing six Americans from the besieged U.S. Embassy in Tehran last year.

The film was produced in Canada with a cast of Canadian actors, most of them refreshingly unfamiliar faces and all of them believable as the American diplomats who narrowly missed being taken hostage when the embassy was overrun by vicious militants in November 1979. The producers of the film have made a big point of its historical accuracy; perhaps as a result, it's not quite the nail-biting cliffhanger some viewers might prefer.

Director Lamont Johnson takes the methodical, docudrama approach to the material, although the script by Lionel Chetwynd manages to give the characters depth and weight; this isn't dry, stick-figure drama like "Pueblo." cJohnson's "Escape" is serious and solid. It's just hard to get very excited about it.

One problem is simple logistics. Unless you are very familiar already with the layout of the compound in Tehran, you probably won't have the slightest idea where everybody is in relation to everybody else once the riot ensues. By the time one of the characters looks at a schematic of the compound, the film is half over.

Not all the heroes are Canadians. Karl Marotte plays James Lopez, the Marine Sergeant who is the first to be aware of the potential explosiveness of the situation as the Iranians fester outside the compound gates. Later, as they stream into the compound, he helps those in an isolated part of the embassy scurry out a rear door. The film leaves Lopez behind at the embassy, where he remained, and follows the escapees who scatter and flee, first to the Iranian-American Cultural Center, then to the home of Ken Taylor (played by Gordon Pinsent), the Canadian ambassador to Iran at the time.

The scenes of the diplomats going slightly stir-crazy in confinement are very well done, and the diverting details include such events as an Iranian worker blackmailing the Canadian ambassador with the simple information that his house is producing much more garbage than usual. A payoff shuts him up.

Finally the time comes to smuggle the Americans out of the country, with faked passports on which the ambassador himself puts a few finishing touches. Scenes at the Tehran airport are deftly tense. As the film ends, the Canadians are shredding documents and smashing equipment as they prepare to abandon their own embassy.

There is little interpolation of actual newsreel footage in the drama -- few shots of Iranians shouting in the streets (who wants to see that again, anyway?). The film is circumspect in not depicting the Iranians as ghouls or barbarians, but shots of them lowering and trampling the American flag, and later burning it, do make the blood boil all over again. Obviously, though the filmmakers were after something more sophisiticated than a rabble-rouser, and most people will learn things about the escape that they never knew before.

Among these is the fact that a French-Canadian journalist, stationed in Washington, put two and two, or whatever numbers, together during the early stages of the crisis and realized that not all those at the embassy at the time of the takeover had been accounted for. A State Department official takes the journalist to lunch and begs him to sit on the story until the Americans and the Canadians are out of danger.

A big fat lunk of an editor tells the journalist to run the story anyway. But he doesn't. He does tell the man from State, "You're lucky it's me who put it all together and not one of your superstar journalists. There would already be a TV-movie and a paperback." Why, the very idea!