Martin dutifully sets the cup down as directed, prepared to stand and await further instruction (or derision, if the case may be), but it seems John is well prepared, immediately issuing a command almost too familiar to second guess. But it's been a long while since Martin had to fetch files for him, and he's reasonably certain there isn't anything he actually needs. That's far beyond the point. Whether or not John has anything specific in mind or this is some kind of setup is the real question here.

So Martin hesitates for a beat, and then, hoping he can manage to strike the right tone, he says, "S-sorry, which file?"

It helps, he supposes, that his confusion is a bit genuine; but more than that he feels a genuine desire to play the game right, to understand the rules, or at least do his best to play willingly into whatever trap John's setting him.