Go to room on Train with Natalya being held hostage by Ourumov
Go to the right side of the room, so that you can get a clean shot of both Ourumov and Xenia
Shoot Ourumov once in head and then kill Xenia. If you manage to kill her, you will get extra time before the train blows up
Drone Gun in Depot
Go to the warehouse in the Depot with the ammo and weapon supply
Get the rocket launcher
Go to the room with the computer system and the drone gun. Destroying the drone gun by aiming the rocket launcher at it and shooting (of course) is a lot easier than using your gun
Use Truck in Dam as Cover
In the Dam, use the truck as protection from enemy bullets
