Adrian saw what the Flame Giant Surtr has started and can only remember what they have spoke about. He was originally not the one that would summon the Flame Giant Surtr to end Ragnarok but circumstances of fate have pointed to him. The moment that Adrian appeared before the Flame Giant Surtr brimming with the energy of the Fates is the moment that the Flame Giant Surtr knew that it was already time.
The continuous interweaving and changing of fate that the God of Mischief Loki has done made the end of Asgard more tragic than before. It should not have ended with all of the gods dying but the God of Mischief Loki killed the Great Star Gazer and even twisted fate to send Adrian to the Void. The God of Mischief Loki that was immune to the whims of fate is no more which is why the Norns immediately went to work.
