Well seeing that Al has been playing for Van I hoped through her and her knowledge of the castle it could enhance our choices as to how to get to the lower levels. But the recon is the natural thing to do. I would guess we wouldn't want to cross the open floor to the bronze doors, the tenticles could reach out through the room. Going to our left toward the alcove with armor seems more logical.
If we can also figure out more about the ley line, the point of intersection could be the rift.
As i see it there are three objectives. (In no order)
1. Find the book. (May be in library)
2. Find the Stone. (Most likely on the German Officer Metzger)
3. Find RPN. (In dungeon cell?)
We can't destroy what we can't find.
Movie wise don't you always free your guys first.