Why did Anakin and Dooku duel in the dark?

Question

Towards the end of Attack of the Clones, Dooku fights Anakin in a darkened hangar. I've never understood, either in-universe or out, why part of the fight is the combatants twirling their lightsabers over their heads in the dark (reminscent of a 'rave party'). Moreover, Dooku was played by Christopher Lee, a champion fencer and veteran actor when it comes to sword-fighting.

So, my questions are:

1. Is there any in-universe explanation of the techniques used in the fight to explain the 'rave party'?

2. Is there any out-of-universe evidence that Lee (or anybody else) challenged Lucas on how the 'rave party' scene looked?

Answer 1

In-Universe

Anakin cut the lighting cable because it was in his way as he walked backwards. He had to step over it, and presumably felt that cutting it would clear the fighting area, removing a slightly random element. It's noteworthy that neither this scene, nor the "fighting in the dark sequence", exist in the original script and appear to have been added at the production stage.

With TWO LIGHTSABERS, ANAKIN attacks. COUNT DOOKU parries and ripostes. It is no contest. ANAKIN is driven back against the wall. He loses one lightsaber. Finally COUNT DOOKU, in one flashing move, sends Anakin's arm, cut at the elbow, flying still gripping his lightsaber.

Out-of-Universe

This sequence was added for a few reasons, some more obvious than others.

To disguise digi-Lee.

Christoper Lee was an old man by this point and largely incapable of fighting with a sword, let alone spinning and whirling. They replaced him with a "digital Lee" in longer shots (replacing his face) and used close-ups of his face to make it look like he was fighting. Having lowered lighting makes it easier to 'sell' the effect to audiences as well as making the animation cheaper and hiding the 'uncanny valley' effect when you have digital characters on film.

Pablo Helman: As wonderful an actor as Christopher Lee is, when we shot this he was 79 years old and so the majority of these moves he couldn't really quite do. For some of the shots we had his stunt double do the action and then on top of that we replaced the stunt double's face with Christopher Lee's face. In some other shots we just replaced him completely.

_{^{Attack of the Clones: DVD Audio Commentary}}

To increase the excitement of audiences

Lucas also felt that lowering the lighting would ratchet up the tension rather than just having more of the same between Dooku and Anakin. Having already seen a fight in a well-lit hangar, the obvious progression is to do something with the lighting. The darkness of the hangar versus the lightness of the sabers created what he referred to as a "tone poem" that audiences would find appealing.

George Lucas: We went from having sort of "level one" of the swordfight with Obi-Wan, I then needed to progress to "level two" with Anakin because each time we have a swordfight, it's got to get more intense ... then I had Anakin cut a cable so I could do it in the dark. I wanted to go back to my old roots of a visual sequence, kind of a 'tone poem', lightsabers moving through dark and making it more of a 'visual' idea then an 'action/fighting' idea

_{^{Attack of the Clones: DVD Audio Commentary}}

It's like poetry. They rhyme. Every stanza rhymes with the last one

It's again notable that he used this same technique in Return of the Jedi in the fight sequence between Luke and Vader, moving from a well-lit stage to one largely in darkness. Audiences who'd seen the earlier films would recognise this sequence and it would generate a sense of nostalgia.

Answer 2

While the previous answer does address why it was dark, it doesn't do much to address why the two combatants were twirling their lightsabers around apparently for effect, so I'll cover that.

This is to do with how the Force is used in lightsaber combat. One of the best descriptions of it that I'm familiar with is from the Revenge of the Sith novelisation, when Obi-Wan is fighting Grievous' MagnaGuards:

...it was not Obi-Wan who would defeat them; Obi-Wan wasn't even fighting. He was only a vessel, emptied of self. The Force, shaped by his skill and guided by his clarity of mind, fought through him.

In the Force, he felt their destruction: it was somewhere above and behind him, and only seconds away.

He went to meet it with a backflipping leap that the Force used to lift him neatly to an emptry droid socket in the ceiling hive. The MagnaGuards sprang after him but he was gone by the time they arrived...Here, said the Force within him, and Obi-Wan stopped, balancing on a girder, frowning back at the oncoming killer droids ...Though he could feel its close approach, he had no idea from where their destruction might come...until the Force showed him a support beam within reach of his blade and whispered, Now.

His blade flicked out and the durasteel beam parted, fresh-cut edges glowing white hot, and a great hulk of ship-sized cargo container that the beam had been supporting tore free of its other supports with shrieks of anguished metal and crashed down upon all three MagnaGuards.

Oh, thought Obi-Wan with detached approval. That worked out rather well.

Now, imagine how that kind of perception would work when both combatants are using the Force, in the same way, and to the same extent. The future would be constantly shifting and changing as each reacted to the danger and each tried to position himself to strike.

It's the reason the lightsaber fights in the Prequels often feel so choreographed - it's because they are. If you can see what your enemy is going to do before he does it, if you let yourself be guided by the Force in every move, you find moments of stalemate, when both are jockeying for position but also knowing they can't win with a single strike at this point. The same is true of the moment in the Obi-Wan vs Vader battle on Mustafar when they both stop striking and spin their blades around before finally trying simultaneously to Force Push one another.