I disagree, the Nolan films are firmly grounded in "a" reality. A slightly stretched one, sure, but so far it's been a series of films without much in the way of fantastical elements beyond what you'd have to accept as simply part of the character. That Bruce Wayne is so easily able to pull of dual identities, embezzle and do the damage he does without getting caught is a bit unrealistic but still not as fantastical as some elements of the BMU. It's a reality grounded in a benign universe without much in the way of magic or super natural.
If Ra's does end up being immortal the Lazarus pit can fit in nicely as being a supernatural element of a forgotten race/religion. It's just q question of how far you can stretch the disbelief of the Nolan-U.
If Ra's does end up being immortal the Lazarus pit can fit in nicely as being a supernatural element of a forgotten race/religion. It's just q question of how far you can stretch the disbelief of the Nolan-U.