Enter the hallway and kill the guard with your knife.

Go through this door and find the revolver. Fight the two guards in the green and the red bedroom.

Take on this armour, don't let it surprise you. Find more ammo to shoot it with at this end. Run to and fro to keep a distance to the armour. Get an axe.

Drop the sub mutant in the bathroom for more health.

Now you may enter this washing room. Finish with the ghost and open the secret door. Mind the water.

From this room shoot the barrels to hit the Super SS. It may only hurt him. Finish him with your revolver. Get the plasma gun. Mind the poison.

Continue north through the western (red) section of the hallway. Drop the guards you meet on your way.

Continue.