Nate and Elena chase after Lazarevic, who has kidnapped Schäfer and taken the Phurba. As Lazarevic's convoy of vehicles hits the mountain road to the monastery, Nate and Elena give chase to remain in the hunt for Shambhala.
This chapter is pretty simple. Nate is on the enemies' trucks, and because of everybody shooting at him, they also shoot the truck causing it to blow up. So whenever you see black smoke or fire, jump to another truck that's near you. Also, if the other trucks have soldiers on them, quickly shoot them before you get on the truck, since you might fall of the truck causing Drake to die. Once you're on the truck with the grenade launcher, keep shooting the enemies' vehicles since it has unlimited ammo. Make sure you don't hit the truck that Elena's driving, but do shoot any trucks that try to kill her.