Find yourself on floor 2 here (red arrow). Find a full ammo clip in this room.

Enter the big hall to the north. Shoot the two guards and hurry forward. Take the health by the northern wall if you need it. Turn quickly around. The two guards in the little room to the south are coming after you. Finish with them. Find more health in the two adjoining bedrooms.

Open the door to this room, shoot the barrel and take the cross. Then fight the armour. You may have to defeat the armour with your own axe. Find lots of plasma gun ammo and a 1-up further into the room.

Open this door and use your plasma gun to shoot the guards around the corner.

Kill the Super SS in this room. Get a cross, and a health chalice.

Fight the three Super SSs in this hallway.

Continue.