The whole “walk down a staircase until you see a door” thing is a very common visioning for entering the Underworld, which (I suppose I don’t have to specify to you, Liryen, but am saying for completeness) is a place to find personal and ancestral memory. On the other hand, it is proper to be skeptical of results of such inductions, because as you allude to, it’s quite possible for the brain to simply make something up. On the gripping hand, one should take care not to squash blossoming long-shining-rememberings because they don’t immediately stand up to scrutiny. On the balancing limb, one does hope they eventually all hang together!