Anakin: YOU TURNED HER AGAINST ME!?
Obi Wan: You have done that yourself.
(He glares at his former master as he decloaks, with Obi Wan doing the same.)
Anakin: YOU WILL NOT TAKE HER FROM ME!!!
Obi Wan: Your anger and your lust for power have already done that.
Obi Wan: You have allowed this dark lord to twist your mind until now....until now, you have become the very thing you swore to destroy.
Anakin: Don't lecture me, Obi-Wan; I see through the lies of the Jedi...I do not fear the dark side as you do!
Anakin: I have brought peace...freedom....justice, and security to my new empire.
(Obi Wan stares at him in disbelief, unable to comprehend what he had just said.)
Obi Wan: Your new empire!?
Anakin: Don’t make me kill you!
Obi Wan: Anakin, my allegiance...is to the Republic! To DEMOCRACY!
Anakin: If you're not with me...then you are my enemy.
(...Obi Wan now realized that there was no other way out of this.)
Obi Wan: Only a sith deals in absolutes...I will do what I must.
(He gets in his position, with Anakin sensing this.)
Anakin:...you will try.
(And soon, he backflips towards his former master right after activating his lightsaber; both beginning to slash at each other wildly.)
(The battle of the heroes...had just begun.)
(After nearly driving Obi Wan to the edge of the abyss, he kicks him away, the former backflipping to lessen the blow before continuing off-screen.)
(Back to Mustafar...)
(The battle rages on, as both master and padawan continue to slash at each other, and at the same time, climb up.)
(But the structure soon floats closer to a lavafall.)
(Realizing this, Obi Wan leaps towards a cable, and takes hold of it, Anakin soon following suit with another one.)
(All it took was one slash for the former to figure a way out of this.)
(He safely leaped into an empty mining platform, and watched as the structure melted and fell down into the bottom of the lavafall, thinking it was over.)
(But Anakin was faster, and was able to run all the way up...)
(...and after a miraculous landing on top of a mining droid, he begins to control and steer it over to the platform his master was.)
(The poor droid drops his payload to melt into the lava as it is unable to continue with its normal programming with Anakin's overriding.)
(Both soaked in sweat and exhausted, they continue to exchange swings at each other, but of course, at a much slower pace now.)
(They eventually stop after 10 seconds to catch their breaths, to which Obi Wan takes advantage of...to try to reason with his student one last time.)
Obi Wan: I have failed you, Anakin!
Obi Wan: I have failed you!
Anakin: I should've known the Jedi were plotting to take over!
Obi Wan: Anakin; Chancellor Palpatine is evil!
Anakin: From my point of view, the Jedi are evil!
Obi Wan:...WELL THEN YOU ARE LOST!
(The two stare at each other, with Obi Wan having given up on trying to bring him back to his senses.)
(He was sweaty, tired...and did not want to continue to fight any longer.)
(And as for Anakin, while also exhausted, he still had a lot of energy left in him to stop Obi Wan once and for all.)
(He coldly stared at him while waiting for a chance to attack him.)
Anakin:...this is the end for you, my master.
(Deeply hurt by what he just said, Obi Wan got back on his guard.)
(To catch him off-guard, Anakin sommersaulted behind Obi Wan, and after almost falling into the lava, the two slash at each other again some more...before entering into their final blade lock.)
(Obi Wan then leaps into a nearby embankment, gaining the high ground while Anakin stared down at him.)
Obi Wan: It's over, Anakin!
Obi Wan: I have the high ground!
Anakin: You underestimate my power...!
Obi Wan knowing what is about to happen:...don't try it...
Anakin: AAAAAAAAAAAAAAARGH!
(Anakin leaps towards Obi Wan in an attempt to attack him from behind again...)
(...only to get the rest of his organic limbs sliced off, causing him to tumble down and stop near the lava river in agony.)
(Obi Wan could only watch in horror...)
(...and grief...)
(...as Anakin attempted to crawl towards him, the Dark Side now beginning to fully consume the former.)
Obi Wan: YOU WERE THE CHOSEN ONE!!
Obi Wan: IT WAS SAID THAT YOU WOULD DESTROY THE SITH, NOT JOIN THEM!
(Anakin continues to struggle almost blindly as his now-former master, driven to tears, continued berating him on his failure.)
Obi Wan: TO BRING BALANCE TO THE FORCE; NOT LEAVE IT IN DARKNESS!
(With these words, he then picks up Anakin's lightsaber, and turns to leave...)
(...before he is stopped by his former student, now fully embroiled by the dark side, cursing him out.)
Vader:...I HATE YOU!!!
Obi Wan heartbroken: You were my brother, Anakin...I loved you...!
(...and with this, his right leg catches fire.)
(The rest of his body soon followed.)
(Obi Wan...could not bring himself to even look at him now.)
(It wasn't the Jedi way, after all...)
(...and so, he ultimately decides to leave him for dead, and runs back to Padme's ship.)