That person credits 'tropes' less than he once did, having worked out some of the hidden rails of causality underneath. But he assigns weird coincidences a higher probability than if he hadn't run into all the weird shit he had. Something is messing with probability around this planet.
It is worth the extra effort to give that force some small boosts and opportunities to mess in his favor, if it happens to be so inclined. That 3% chance is not the only equivalence-class of outcome where Carissa Sevar defects for some reason, today, as a result of causality playing out from his plan.
Therefore, that person has placed himself where he can hear a Sending (he's protected against Demands, obviously).
And he also timed his probe by when - according to Ione Sala's allowable pre-Nefreti knowledge - Carissa Sevar would just be waking up, if she was sleeping according to her usual Ring of Sustenance habits. He timed it for then plus 20 minutes. That, he reasoned, ought to prevent Carissa from having already hung spells that day; and would give Carissa a chance to hang spells useful in defecting, if she ended up put under a Mind Blank to prevent Wishnapping by him, and the artifact headband boosts made her realize that serving Asmodeus was stupid.