Ed: Note, much talk of "To Buddhists this means" and "In Buddhism this means...". If you preface this with "Tibetan" as in "In Tibetan Buddhism this means..." you might be closer to the truth. By the way, the Buddhist, it might be argued, does not "...seek for the soul to become one with the universe". And if they did the universe is most certainly not "Nirvana" This would be difficult after all considering that there is neither a "soul" or indeed a "universe".
Bayreuth as Bardo: Schlingensief’s Parsifal Production
Edward A. Bortnichak and Paula M. Bortnichak (University of Pennsylvania)