Setesh and Slathissin hear nothing, but Katria catches brief flashes of words coming from an adjacent hallway.
SpoilerVoice 1: "...shouldn't be here. Dark Apostle Akaduros-"
Voice 2: "What he doesn't know won't hurt us. Come brother. We have a-."
Voice 1 (in a low, hissing tone): "Shut up! It's bad enough we're going to do it. Don't say it out loud - the walls have ears."