Oh. Okay.

So if someone wakes from a definitely non-lucid dream that took place in the catherdal and she remembers being told a password by, say, an otherworldly monk, that exactly matches Mindraker's chosen word, the results are not valid?

I'm not sure that makes sense. Though I have a feeling it would take fairly high-end lucidity to succeed in getting the password, isn't there a chance that someone might bumble on it unconsciously or, better yet, have it handed to them without ever knowing it's source? There ought to be room for accidents.