In the temple where you need to retreive part of the book of Nod, my game crashed while saving. No big deal, I thought, since it still saved successfully.
I did notice, however, that the enemies I had just disposed of before saving had returned.

Turns out the entire temple had reset itself, except for my location in that temple, so when I got the book of Nod fragment and I backtracked my way out of the building, I found myself facing a locked door that can only be opened by a switch on the other side of that door.

Is there a way to fix this, perhaps with a cheat code? Thanks in advance.

EDIT: I solved it.

I used the cheat "jump".
"jump Monastery" specifically.