Mycroft isn't particularly insulted by Martel failing to be a perfect gentleman. The interaction echoes the way he's treated by the more no-nonsense politicians around 10 Downing (the ones who don't know what he does). He wouldn't call it 'a nice reminder of home,' but it makes it easy to fall into familiar patterns. Not having to think or care about interpersonal relations is one thing Mycroft often envies his little brother, and right now being able to navigate a conversation on autopilot is a small mercy.

He nods and follows Martel as the other man leaves the office, the now-familiar sight of the library's main lobby soon coming into view. He's led to a section of shelves that is around an area he'd been in earlier, but far enough in a seemingly unrelated direction that he hadn't noticed it before becoming distracted by other subjects. (It had been early in the day, and the organizational system had taken an hour or two to learn thoroughly.)