After he finishes with his day-job duties (separate from attending diplomatic functions to stand around and look handsome) he attempts to let himself out of the room with the comconsole and all its data to sift through, only to find that the hallway has turned into a bar.
He looks over his shoulder. The office is still normal. Which is to say there are no other exits.
Ivan goes into the bar, squinting.
When he comes back from that, Miles is still there and they have moved on to a different Holmes story and a different history book.
Ivan, slightly tipsy and very worn out from his night on the town, says, "You bookworm twins are going to have to move to Miles's room unless you want to switch to unadulterated telepathy, 'm going to bed."
"...I should probably sleep at some point. The books will still be here in the morning. 'Night, Ivan. 'Night, Mark."
And back to his room he goes.
The next day, after he does his work, he finds his room empty, presumes that the twins-six-years-apart are in Miles's room, and he knocks perfunctorily and lets himself in.
"One, yes you do, two, scientific consensus has changed in the last thousand years, three, you've seen me do it, you clearly know that it works," says Mark. "Hi, Ivan."
"Your arguing about books has a time limit," says Ivan, "Miles, th'captain wants you at the little shindig the ambassador's hosting for the new Zoave Twilightan - Twilightian? Zoavian? Whatever the word. The new ambassador from Zoave Twilight."
"Miles wants me to be his substitute because he thinks it's going to be boring. I don't want to be his substitute, because I know it's going to be boring."
"I'm very sociably inclined. Anyway, Miles, dress greens, look sharp, it's in an hour."
"Suck it up," snorts Ivan. "I'm going to go change. But call me in if you decide to argue with a mirror."
And he and Ivan go and meet various assistants of the Zoavian ambassador (Ivan inquires of his the demonym and she tells him that's what it is) and serve as their escorts at the party. The food's lovely.