The Final Moment of the Buddha's Realization

“Siddhartha Gotama sat for one last time under the pipul tree with the adiṭṭhāna that he would not get up till he became realized. He battled the beautiful as well as the ugly and fearful illusions of Māra successfully that night and at the same time had very profound insights into Reality, the final one being that into paticcasamuppāda which destroyed the last vestiges of avijjā and Gotama became the Buddha, the Tathāgata, ‘Thus Gone’.” It was a momentous event! I want to understand this profound moment and, therefore, have some questions: 1. What happened to Gotama when he became the Buddha? Of course, as Buddhists we understand that there was no self at all to begin with, but that was not experientially realized till asmi māna, one of the last fetters, dissolved. So, Gotama did not realize nibbāna because that would mean that his ‘I-am-ness’, his māna, continued into nibbāna, which is unacceptable. Should we say instead that ‘there was realization’, an impersonal phenomenon, as the asmi-māna vanished? Could we say that this realization entailed an ontological shift from the puny, illusory self to the unconditioned Nibbāna? But then wouldn’t that still be some kind of eternalism? Or: 2. Did Gotama, the conditioned, illusory self ‘die’ at the time of his realization and the nāma- rūpa, that it once was, continued by the sheer force of its unspent past karma which on exhaustion then led to Parinibbāna of this psycho-physical being? Was the Buddha this nāma- rūpa that, metaphorically speaking, ‘translated’ the unconditioned Reality for puthujjana like us and made it possible for us to tread the path for its realization? But then what happened at Parinibbāna? What remained? Nothing? Doesn’t that sound like annihilationism? Or: 3. Did at Parinibbāna, with the extinguishing of the final vestiges of conditioned being, the Unconditioned shine in its brilliant, impersonal glory? Beyond Being and Non-being? Beyond anything that can ever be understood? Or would that be mere linguistic gymnastics? I want to understand what actually happened!