[LEVEL 10 SPOILER] Logical?

[Encephalon]

I remember reading his note where he stated to the effect: "I should've known better..." when then which he continued on about being a very experienced adventurer and sort of "kicked himself" for not being more aware of his surroundings.. Sounded like a "foolhardy" mistake he made by not paying attention to his surroundings (even the best make mistakes)

I found your interpretation quite plausible! Toorum is just human after all, and who of us haven't made a mistake which we, with hindsight, couldn't quite fathom how we managed to make.

the backstory to Toorum and why he is down there and what he is doing is on the first two pages of the instruction manual that comes with the game...

I interpreted the story at the beginning of the game manual to be the story of the four adventurers you start the game with, as it clearly states that it's several prisoners bound together by chains. However, from Toorums notes and the description given by Magister Alarast, this description clearly show how Toorum, and countless others, became trapped within Mount Grimrock.

[Pajamas]

Well, couple theories I got, so let me take a crack at it.

1: Toorum was disguised as a monster, but was uncovered. This is a simple one. He disguises himself as a monster, or something that would fit in as a monster. After finding the secret room, soon to be his tomb, a monster purposefully pushed the button to lock him to his death, after cunningly finding out he was a human. The most simple one I could think of, and explains his little tidbit on how he thinks they knew that he wasn't one of them.

2: Just random unlucky luck. This one is up to anyone's interpretation. Either a survivor ran around and hit the secret button, either dying shortly after or to purposelessly kill Toorum. Or a ogre slams into the wall in his sleep, closing the door.

3: Simply insane. My favorite, honestly. He just went mad and locked himself in a room. Simply couldn't stand the dungeon anymore. My favorite just because it is the most likely.

[Dhauntyr]

Toorum disguised as a monster would've been amusing. Actually, I would've loved to see that. I wonder if some of the other Goromorgs noticed that he may have appeared a little... "short". Long hood; where would be the Illithids?

[Thels]

EDIT: B t w wasn't the name of the dwarf fighter that joined you in EoB also Toorum?

That was Dohrum.

[t0tem]

Dopey?