There's a brief moment of spinning horror before Asmodia stops trying to see the world from Keltham's dath ilani viewpoint quite so hard, and remembers that she is in Golarion.
Random numbers? Prophecy is broken but it's not that broken!
AUGURIES! Use Auguries every time to check if it's the right time to hand him an excerpt! They're fallible but if Keltham doesn't do too many checks we'll have a CHANCE of fooling him!
...if they've got no Auguries prepped and no scrolls of those, then they're all going to die, now, but it won't be Asmodia's fault. She really felt like she was doing an unusually good job here involving some huge personal and professional risks, that gave Cheliax the best chance it could have had with just her own efforts, if other people did theirs and were adequately prepared.