What do you need to know?
A player had a epiphany.
Well let me back up some...
Convergence Point allows people to "do things" rather than just kill people through damage. Damage generate stun, wounds, and impariment points, all with a single damage roll. The first two are self explanatory (temporary damage, permanent damage). Impariment points allow you to "buy effects". You can push a target back, or have them trip (due to the hit), or drop weapon, or temporary blind them, or cut off their arm, or knock them unconcious or kill them. In short, you can simulate more realistic or more cinematic combats. If you have a point or so, you hit them with a tiny effect. This can give you advantages over the target. If you managed to hit and keep four impairment points, you can "take them out of the game", interpret that as you will. Effects have cost between, and costs are dependent on the importance of the character (mooks take 1 point to do anything you want to them, minor NPCs half the points it takes to do the same with a full NPC).
Actions are also story driven. You can do more than simply, I hit him/ I block. You have an impulse of time, it ranges anywhere from 3-20 seconds. So think of it as time on camera in a movie. A successful attack roll can be interpreted as a quick attack - a series of jabs or ballet of damage and death worthy of a John Woo film. The more story/ description you can generate to fit the results of the roll, the more eps you can earn for the scene.
The real important part was the player's epiphany, that killing the villian really didn't matter. The player came from a D&D/ Diablo/ Video Game backround. Targets were only neutralized by death and combat was nothing but a slug fest toe to toe, mashing button/ rolling dice. (He was learning that description and things were his friend as he saw his co players racking up extra player points/ experience through simple description).
Instead of killing the target dead, he realized if he was merely "mostly dead", it solved the problem/ issues at hand and did not have the annoyance factor of the GM having to "rescue" the villian after apparent death. I mean, you killed him. He should stay dead. Yet GMs often have obscure death or even flimsier excuses as to why their favored NPC or other villians did not completely die.
He had watched the perfect combination of entertainment to teach this lesson.
Holmes apparently killed Moriarty at the falls. However, he came back a few years later. We have all seen this happen in the source material (comics, movies, stories). Yet we seem suprised when GMs do it in games. After all dead is dead for PCs right? Why not for NPCs? Well, there are other things the GM needs to have in place to keep their plots going. So the story continues.
The player realized "this works". He can kill him, without actually killing him (standing over the body as it cools). The NPC is out of the game. By "gift wrapping it" for the GM, he just keeps the story going for the GM. (And earns a bucketload of xp from a grateful GM)
In Blake 7, we learn the lesson of "If you don't kill them, the GM is less inclined to write up a tougher opponent". The Seven defeated Travis, minion of Servalan (president of the tyranical Federation). Several of them wanted to kill him, but Blake stopped them. "We have taken his measure. We can stop him any time. If we kill him, new people will be sent after us. If we let him live they will keep sending him after us. I would rather take the known than the unknown. "
Thus he generated a "continuing villian" that was a minor challange.
What else do you want to know?
It is better to leave a character alive than kill them. You kill them, they make a new characters. You leave them alive... as a prisioner, or trapped in some awful situation, or lost in space. That has drama. That gives the player something they have to overcome, new plot directions, new things to do. The character is now embroiled in something they can't simply get out of.
And the advantage of it, is that all the plotlines, meta plotlines, and other lines, are still intact. They might be a bit delayed by the events, but they are there.
If you kill them, they need new characters and then all the hassle of bringing them into the campaign with the rest of characters.. inserting new plotlines... new relationships... the inequity of the skills... providing motivation for their the joining up and getting involved.
In short, keep them alive.. just load on the drama. It works for PCs and NPCs/ villians.