The rivals meet before the battle

As we get near to the Battle of Borodino, Tolstoy shifts our POV to Prince Andrei, and here we get another one of those extreme interior moments in which the character experiences or observes something that makes him ponder his own fate and the entire nature of the universe - a little like what Joyce would later call an epiphany, but in Tolstoy it's all a little bit more heavy-handed and explicated. Prince Andrei looks across the battlefield, actually just a field at this point, and imagines that he might die in the battle. And he sees all the trees and hills and the flowing river (I think he remarks on this) and realizes that the world will continue even when he is no longer in it, and he tries to imagine how this can be so, and his mind cannot really comprehend this all-too-obvious fact. Hasn't everyone had that thought, and tried to imagine what "life would be like without you"? It's sad and shocking feeling, both egotistical - aren't I the center of everything? the very reason for its being? - and self-deprecating to the extreme: I am nothing in this world, I pass through and change nothing, the world will go on. After this realization, Pierre literally stumbles onto the scene and Andrei uneasily welcomes him. These two have had a complex and strained relationship for hundreds of pages (7 years) now, even though they have rarely been in a scene together. Pierre visited Andrei when Andrei was recently widowed and deeply depressed, and he helped to bring him back to life - which Andrei still, I think, resents somewhat. Now, though they don't know it, they are each in love with Natasha - Andrei jilted by her, and Pierre turning away from her because he cannot marry her. Gradually, this conflict must rise up and turn the friends on each other, destroy their friendship, or bond them in some mysterious way yet to be seen.