"So we can't assume that the pilot/copilot conversation actually took place during take-off."
This is like playing Russian telegram, where each person whispers the original story into another's ear, and by the time it goes around the circle it bears no resemblance to the original story.
The only person on this thread who said anything about "takeoff" was the original poster, a non-aviation person who, by writing "when taking off," could have meant anything from pushback to liftoff. We haven't the faintest idea whether they were running checklists, taxiing, back-taxiing, position and hold, rolling, V1...
So everyone should continue to theorize about whether they were flying a back-course localizer, taxiing on a parallel runway (in the Northwest Territory???) or taking a bearing from over Sarah Palin's house. It's so much fun.