Doesn't it seem like achamian should be more concerned about catching a glimpse of a "sorcerous bird?" Even Inrau recognized the synthese as consult when he saw it, even if he didn't know what a synthese was. It bothers me that Achamian didn't freak the fuck out when he saw this.
Also, later in chapter 12, as Aurang is having an (epic) conversation with Kelhus, Kelhus states that Achamian had discussed snythese with him, indicating Achamian has enough information about synthese to have known what it was. I think glimpsing a sorcerous bird should have set off more alarms, with greater urgency for Achamian. Then again, maybe it did, as Kelhus sets the trap for the skin spy.
Chapter 12 is immense.