Teru, the point was that the mind is able to do things such as make up what is not there. Yes, there is light at the end of the tunnel, but more of along the lines of being judged at the pearly gates or angels with little harps (I'm quite sure angels are supposedly something like three-headed dragons, instead of the romanticized fluffy-winged creatures of today), your brain is powerful enough at times like that to produce images that don't exist. Like you said, when that line is crossed, you become delusional. That line would probably be crossed at the point of dying, where they probably receive the vision, and not at the actual time of death. Not that I have any scientific proof, but it's speculation --- I'm sure the links you provided have more accurate data.