Aidan blinks, and spends a second wondering whether John means that there were no witnesses to his sleep, or that no witnesses ended up in his bed. A copper's instinct, pay attention to double meanings.
"Then let me bring you up to speed," Aidan offers, because the point is that John's not heard a thing, and things oughta be heard by the fella. Except he pauses, and points at Zeta. "How freely can I be talkin' here?"