I am aware of that, but I believe it to be an anomaly with the Vex, as this sort of this is not at all normal, and given the condition of the Guardian and Ghost, was likely forced upon the Guardian rather than him making the choice. For this reason, I stand by what I said in the post. As for your comment about the Ghosts and the Crucible.. I'd like to see a source, because I have never seen anything to suggest that.

Grimoire:dead ghosts "Battered and drained of their Light, these Ghosts are nevertheless valuable for the information they preserve." So you can drain the Light of a ghost and therefore kill it which means that Ghosts do not have an infinite amount of Light.. Ghosts are the Light source of Guardians so there are two ways of killing a guardian. Guardians can be permanently killed if their light is drained by a powerful enemy, or if their Ghost is destroyed. You can not "drain" infinite Light.. For example in the "dark beyond" mission we find a dead guardian and his ghost inside drained by its light.. It is dead no more Light.. If it had infinite Light then we simply stop the ritual saving the Ghost from the draining process and then it goes out to ressurect its Guardian.. But that is not the case.. They called "dead" ghosts not "captive" ghosts.. We come to the conclusion then that Ghosts have an X amount of Light that they can use to ressurect-heal-empower Guardians and you can drain that amount of Light out of them permanently killing them.. I don't remember the exact grimoire where it is states that a ghost uses little of his Light to revive guardians in the Crucible but using the same logic you can assume that a Guardian has a death limit..

You make a good point, and I should have clarified. Guardians and Ghosts have a limited amount of Light (although that reserve is quite large), but a nigh-limitless amount of [i]energy[/i]. We have no records of Ghosts only having a limited amount of resurrection; some Guardians have been revived hundreds or even thousands of times. Therefore we can conclude that while Light is not a renewable energy source (at least not by natural means. See Ghost Fragment: Cabal), it provides so much energy from such a small quantity of Light, that the amount of energy that Guardians have could be considered nearly unlimited. Hopefully that clears things up.