Resident Evil- Dead Aim- Help I'm stuck!

[gvds]

I have finished the scene with the 2 Hunters.
I have saved my game in the Lower Decks Save Room.(typewriter)
If I use the lift I suppose I'm in the Boiler Room...?!
Here I am really lost: I can enter a couple of doors on the other side of this 'room'. And after walking in a long dark hallway I'm always ending up in the same room where I started !?!
I'm really lost.
Can somebody help me, please? What am I doing wrong?
If I am not mistaking I should have to go into the gray door tiny-ly labeled "PRIVATE". But I can't find it. :bucky!:

TIA.