Marshal Davout is Napoleon’s right-hand man. He’s one of those miserable people who gets off on complaining about how miserable and overworked they are. Also, he’s rude and unpleasant.
Balashov finds him doing accounts sitting on a barrel in a shed, even though he could easily have found a house and a desk.
Davout demands that Balashov give him Alexander’s letter. He has dinner with him, still sitting on his barrel, then finds him a place to stay.
Finally, four days later, Balashov is about to go see Napoleon in person like he was supposed to.
What’s happened in those four days? Oh, nothing, except now it’s Napoleon who is living it up in the exact same mansion where Alexander was staying when he gave Balashov his orders. Meaning that while the French were sabotaging Balashov’s diplomatic mission, the French army has taken over the city of Vilna and moved even further east.