Here's the entire confrontation, from start to finish.
As Meetra and Scourge battled the Guard, Revan charged toward the Emperor.
His opponent stood perfectly still, focusing and channeling his power. At the last possible instant, the Emperor unleashed a wave of energy that swept Revan off his feet and sent him flying backward.
Revan twisted in midair so that he was able to roll with the impact when he landed. He quickly sprang back to his feet and advanced again, moving more slowly this time.
The Emperor stood in the exact same position as before; it was as if he hadn’t even moved. Revan began to sense the oppressive presence of the dark side weighing down on him. The Emperor was trying to crush his will: to dominate and enslave his mind as he had before. This time, however, Revan was ready.
Instead of charging forward, he opened himself up to the Force, letting both the light and the dark side flow through him like twin rushing rivers. But instead of focusing or channeling the Force, he released it in its purest form.
There was brilliant flash as the air between the two combatants lit up. The energy unleashed was powerful enough to send Revan staggering. The Emperor, unprepared and with much of his strength diverted to his effort to dominate Revan’s mind, was sent flying backward.
He landed in a heap on the floor and Revan raced toward him. The Emperor rolled over, lifted himself up on one knee, and his hands flew forward as he hurtled a bolt of dark side lightning at his enemy.
Revan intercepted the bolt with the blade of his lightsaber, though the impact stopped his charge dead in its tracks.
The Emperor unleashed three more bolts in quick succession. Revan batted the first aside with his lightsaber, ducked the second, then deflected the third back in the direction of its source.
It struck the Emperor in the chest, sending him sliding several meters back on the floor. For the first time the Sith’s emotionless veneer cracked as he let out a primal hiss of hate. The sound sent shivers down Revan’s spine.
The Emperor rose to his feet, his robes smoking and singed where the lighting had struck him. His black eyes flashed red, and he raised both hands high above his head.
Revan knew he was gathering his power to unleash a swirling storm of pure dark side energy, just as Nyriss had done. The Jedi quickly calculated his options. Realizing he couldn’t close the gap between them quickly enough to stop the assault, he gathered his own energy and spread his hands before him, ready to catch and absorb the Emperor’s attack.
A dozen bolts of purple lightning arced from the Emperor toward him. Revan tried to draw them in and contain them, but the Emperor was infinitely more powerful than Darth Nyriss had ever been.
Revan’s body was engulfed in agony as the electricity coursed through his body. His skin began to boil and blister, the flesh of his face melting and sticking to the superheated metal of his mask as the Emperor poured more and more power into him.
Through the haze of indescribable pain, he saw T3-M4 rushing in to help him. The droid let loose with his flamethrower, bathing the Emperor in fire. At the last instant the Emperor cocooned himself in the Force to save himself from being incinerated, breaking his focus on Revan.
The Jedi collapsed to the ground, burned but still alive, the hilt of his extinguished lightsaber lying on the floor less than a meter beyond his grasp.
Almost too weak to move, Revan managed to raise his head just in time to see the Emperor turn on the brave little astromech. A tremor rippled through the air as the Emperor unleashed the full power of the Force against the defenseless droid.
T3 never stood a chance. The little droid exploded into a million pieces, internal circuits and external casing obliterated in a single instant.
“No!” Revan screamed from the ground as bits of his friend rained down on him in the form of unrecognizable shrapnel.
He tried to rise, but his injured body refused to respond. Instinctively, he called on the Force to give him strength and heal his wounds.
The Emperor was approaching him with calm, purposeful steps. Once he reached Revan’s side he calmly bent down and picked up the Jedi’s fallen weapon, igniting the blade.
The healing properties of the Force were powerful, but Revan’s wounds were severe and he needed more time to restore his strength. Helpless, he could only stare up at the Emperor as he raised the lightsaber to deliver the killing blow.
Even as she called to Scourge to help, Meetra was already sprinting toward the far end of the throne room. Scourge hesitated before joining her, taking a moment to survey the situation, memories of his vision of their failure still fresh in his mind.
What he saw was not good. Revan was being electrocuted, his body spasming uncontrollably as the Emperor blasted him with dark purple lightning.
Revan’s astromech launched a jet of flame at the Emperor, freeing Revan, who collapsed to the ground. In retaliation, the Emperor disintegrated the offending droid, strode over to where Revan lay, and picked the vanquished Jedi’s lightsaber up off the floor.
It all happened in the space of only a few seconds. Meetra was moving fast, but she was too far away to stop the Emperor from eviscerating the prone Jedi at his feet.
In desperation, she hurled her lightsaber with a wild sidearm throw, guiding it with the Force so that it spiraled end-over-end to intercept the descending blade, knocking it from the Emperor’s grasp and sending it skittering across the floor.
Suddenly empty-handed, the Emperor took a quick step back. His attention had been focused solely on Revan; Meetra’s trick had caught him by surprise. Scourge realized that if she had aimed at the Emperor instead of the blade, she could have ended his life even as he ended Revan’s. But her instincts to save her friend overrode her desire to kill her enemy, and Scourge could only lament the lost opportunity.
Meetra was still rushing forward, using the Force to return her lightsaber to her waiting hand.
Sensing hesitation and uncertainty in the Emperor as he tried to evaluate the strength and weaknesses of his new foe, Scourge rushed forward to join Meetra and Revan.
Meetra had placed herself between the Emperor and Revan, valiantly protecting her wounded friend. As Scourge reached them, Revan managed to stand up again. He reached out with an open palm and his lightsaber sprang from the floor and into his waiting grasp.
The three of them stood side by side, two Jedi and a Sith Lord against the Emperor.
“I expected better from you, Lord Scourge,” the Emperor said.
Scourge wondered if he was stalling for time so his Guard could break through the sealed door. There wasn’t much chance of that, however; by the time they broke into the throne room the battle would already be decided, one way or the other.
“He has seen the depths of your evil,” Revan declared. “He stands with us now.”
“Then he will die with you, as well.”
“You can’t defeat all three of us,” Revan said. “United, we are stronger than even you.”
“That remains to be seen,” the Emperor replied.
For Scourge, the universe suddenly seemed frozen in place, as if time itself had stopped. He realized he was at a crux in history; fate and destiny would be forever altered in the next few moments.
The Force washed over him in a wave, and a million possible futures flickered through his mind simultaneously. In some the Emperor was no more; in others he had transformed the entire galaxy into an empty wasteland. He saw both Revan’s triumph and defeat in the throne room; he saw variations of his own life and death played out over and over in every conceivable way, shape, and form.
He had to choose, but there was no way to know which was the most likely outcome, or what actions of his would lead to which results. Revan had said visions could guide the Jedi, but for Scourge they brought nothing but confusion.
The moment passed and the universe began to move again, though everything seemed to be happening in slow motion. Revan and Meetra stepped forward, ready to initiate the final confrontation. Scourge knew he had to act now; he had to make his choice.
In a sudden moment of clarity he saw the Emperor lying defeated at the feet of a powerful Jedi … but that Jedi was neither Revan nor Meetra. And the Sith Lord knew what he had to do.
Instead of advancing with his two companions, Scourge stepped to the side so that he was standing directly behind Meetra. There was a flicker in his consciousness as the universe snapped back to full speed, and he slid the blade of his lightsaber between her shoulders.
Meetra gasped and toppled forward, dead before she hit the floor. Revan’s head snapped to the side, shock and horror emanating from him even though his mask hid his expression. The distraction gave the Emperor the opportunity he needed, and he unleashed another blast of lightning into the Jedi’s chest.