During the course of the film, an early example of this unfolding is the briefing scene at Nha Trang, which is where Willard gets the assignment to go and kill Kurtz. And there were a number of wonderful peculiarities about that scene. Francis [Ford Coppola] also shot that scene, interestingly, in a semi-documentary style. It was about ten minutes long as it was originally shot.

It's not that long in the finished film but his instructions to the camera operator, who did not speak English, were, 'You are photographing these three men; the general, the CIA agent and the Harrison Ford character – Colonel Lucas, I think his name is – from Willard's point of view. Willard is hung over and whenever you, the camera operator, feel bored, I want you to pan to somebody else, look at something else. Don't feel that you have to stay on the same actor. Even if the actor is talking, you can pan off of him.'

So, out of all of the number of takes, which were many, of this scene, as I looked at the material for this, as I was cutting it, I could never rely on this take to be all of the General's speech or all of the Harrison Ford material because in, right in the middle of the speech, in this take, the camera operator would pan to the window because he felt like it. And then he would pan past the General, who's talking over to Harrison Ford and then back to the CIA agent and then back to the General.

So, then I had to do a grid map of each take: how many, each line of dialogue in the scene, is it on camera or off camera? So, kind of like a script supervisor would do but after the fact. So now I had Xs where lines of dialogue were covered and blanks where it was not covered. The great thing about this from a film-making point of view is that it kept the actors on edge because they never knew whether the camera was going to be looking at them or not.

Whereas under normal circumstances, you say, 'Okay, we're going to shoot the medium shot on the General', and the General gives the speech and he knows that the camera's going to be looking at him for the eight minutes of the speech. None of that is happening in this scene. It's wandering around seemingly randomly. But it all has to do with what the camera operator was interested in at that moment.

A number of side-effects of that are that all of those actors are looking at the camera as if they're looking at Willard, which is generally something you don't do in a film. You look to one side or the other.

So now I'm looking at the camera here but normally I'm looking at somebody else to the left of the camera. But that scene violates that rule. However, when you cut to Willard and Willard is looking at them, he's not looking at the camera; he's looking to camera, to the left of camera. And then back to them and now they're looking at camera. So, technically it should not work. It should be very disturbing. And it is disturbing in a kind of unconscious way. But that was how Francis shot the scene and it had a wonderful effect on it.