Catch up with the train and find the Dark One | Chapter 21: Khan Metro: LL Guide

Wait until you regain control over your character and get out of water. Go around the trap with the cans in one of the next tunnels (stick to the right-hand wall as closely as possible). Examine the next room to find a machine gun, ammo and first-aid kits. Finally take your seat in the car to finish this short chapter.