Nethys can show His vision in advance to an otherwise uninvolved Lawful god who swears to inaction, Gruhastha being an obvious candidate, who then will not intervene in matters at all; and Gruhastha's testimony later will be some evidence that Nethys did glimpse that related possibility.  For prophecy is shattered and Nethys genuinely couldn't predict so much detail, without having glimpsed some related possibility.

But it's stronger evidence, if matters do not play out too differently from Nethys's visions.  The more visibly credible it is that Keltham would have come to the Starstone in time and with the same determination, the less likely Pharasma is to say to Nethys, "Let's die together in a fire."

Nethys can show His vision in advance to an otherwise uninvolved Lawful god who swears to inaction, who then will not intervene in matters at all; and that Lawful god's testimony later will be some evidence that Nethys did glimpse that related possibility.  For prophecy is shattered and Nethys genuinely couldn't predict so much detail, without having glimpsed some related possibility.

But it's stronger evidence, if matters do not play out too differently from Nethys's visions.  The more visibly credible it is that Keltham would have come to the Starstone in time and with the same determination, the less likely Pharasma is to say to Nethys, "Let's die together in a fire."