The words Owen hears in the Dark Place and repeats in an ethereal growl are "Melenkurion abatha. Duroc minas mil khabaal." This is a reference to the Thomas Covenant series of novels by Stephen R. Donaldson. In the books, these are six of the seven Words of Power used by the people of The Land to summon Earthpower and Law, natural (and inherently good) magical forces. See more
[Martha has asked Owen to tell what death is like
There was a light, a tiny speck of light and I was rushing towards it, like down a corridor, and it got brighter, and brighter, then suddenly there were these gates... these big, pearly gates and there was this old geezer and he said, "You've been a very naughty boy!"