The atmosphere in the Judging Hall was stretched so thin that it seemed like it would snap at the slightest blink of an eye. On one side of the hall sat the Master Judge and his guards, his hand gripping a metal gavel that could either cause the greatest of pleasures or the most torturous of pains. On the other side of the hall sat the Defendant. Between them could be felt a great animosity, so powerful as to push the spectators against the walls; being pushed away from the emanation of hostility that - if one approached it - would force them to fall and curl up on the floor, to give up, to simply wait for it to stop.
The Master Judge's gavel came down as if in slow motion, and crashed against the stone table with a force that would have cracked a femur in half.
The eye had been blinked. The air was emptied by the reverberations emitting from the tremendous crash of the gavel. The great hostility disappeared, replaced by something even worse: the feeling that one's role had changed from predator to prey.
The Defendant's face contorted. "I predicted this."
He stood up.
"I would expect nothing more from a man in the pockets of the Enemy."
A gasp could be heard, and the guards were now on edge, with their guns at the ready. This was a very serious accusation. Almost all men who were found to be guilty in the Judging Hall would be at this point trying to be as sympathetic as possible to lower the severity of their punishment. Yet this Defendant was not doing that. He was almost guaranteed death.
The Defendant's plans, however, did not involve death.
From seemingly nowhere he pulled out a sword, and before the guards could react, he -
What science-based superpower, in an otherwise superpower-free world, could someone have to make the sword a viable weapon in modern times?
When I say modern world, it is likely the enemy will have common modern defense or attack equipment. Expect guns, bulletproof vests, tasers, and the like. (The character doesn't have to beat a tank, but the more overpowered you make the character while still keeping it plausible, the more bonus points you get!)
The superpower itself must be science-based. It can be caused by natural or artificial causes, but please make sure it is feasible, not just possible! For example, a person who gets super lucky and whenever he uses a sword quantum tunneling makes it immediately go through the nearest person's chest is completely infeasible, because the probabilities are just way too low.
Note that the character is not stupid. In fact, in order to develop the science-based superpower, it is likely he must have made some great advances in scientific fields, and therefore is most likely extremely intelligent. Before going into any situation, he would weigh up the pros and cons of other weapons - such as traditional guns, lasers, railguns, darts, bombs, or the like - and would somehow choose the sword. Why would someone do that? What superpower could they have, that would somehow make the sword a better choice than a laser or simply a gun?
The materials of the sword aren't determined ahead of time. Pick whatever you like! However, it has to at least follow the spirit of a sword, even if it does emanate an aura of RGB and look pretty cool.
Note that what makes the sword a better choice has to be applicable in the majority of situations. For example, when fighting in a fragile spacecraft a sword + inhuman reaction times might be a better choice than a gun to avoid puncturing the hull, but a sword must be a better choice not just in (rare) space-based combat but also in (common) ground combat.