Don't Forget About Me (Previously, Keith Isn't Dead)

Keith is under the impression he's not wanted, so it only makes sense to him that, should the situation arise, he would be the better candidate for being sent god-knows-where by a wormhole aimed directly at Voltron- the team, well... the team just wants Keith back.

or

Keith Self-Sacrifice Kogane lands himself on a hostile alien planet and finds himself in the hands of merciless alien researchers who don't fully understand the concept of pain, nor the concept of humans. And they want to know more.
The question is, can the paladins find their missing friend before it's too late, or will their duties as Defenders of the Universe sidetrack them enough that Keith is pushed to the backs of their minds?

BEING SPONTANEOUSLY AND IRREGULARLY REWRITTEN