[DAMN he's moving up in the ranks now. He looks briefly surprised, but politely nods, at least...]

Thank you...? [Still a hint of a question in his tone though because Shijima, why.]

To me, he seemed like a straightforward person, so it's difficult to imagine him being good at lying... But if the evidence lines up with what Bigby is saying, then certainly, some level of deceit was involved. I just can't determine where it may have begun or what it might have led to.