His attendance to the summoning from Golgoth had given Rowan everything he needed to find the gods of Trion in their respective Vaults. The Rune that the God King took precious seconds investigating was like an address and a beacon and while Golgoth was busy checking the durability of the vaults, Rowan was busy copying it.
He had never expected to be given such an opportunity, because he knew the God King checked the status of the vault merely two decades ago, and before that he had checked it a million years back.
Perhaps the death of the universe and the paranoia of the God King was what made him recheck the status of the vaults, but his careful actions only opened him to the influence of Rowan who did not miss this opportunity.