riddle - The Thirteen Doors of Aj Noc'la

_{An entry in Fortnightly Topic Challenge #39: Deep Down in the Dungeon 1.}

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Having finally defeated the tyrannical wizard Aj Noc'la, your party makes its way through the door at the rear of the throne room. Presumably the dimly lit archway leads to the treasure vault...

"I wonder what he meant by 'exiting through the gift shop'...", the party's rogue muses aloud, recalling the wizard's hysterical, dying words. By way of answer, the air is split by a thunderous crack, as the door slams shut behind you. Spinning, you scramble to reopen it, but instead find only solid stone. Then, staring in disbelief, you watch as a gently glowing inscription etches itself across the wall:

Gaze upon this thing of wonder,
'Neath a sky where stars align.
Then with heavens torn asunder,

From the shadows comes a sign.

In the runes, the truth is dawning.
Can you hear which door will save?
Make your choice, but heed this warning:
Twelve doors hide an early grave!

Turning again, your eyes are immediately drawn to an enormous structure, floating weightless in the centre of the cavernous room. It is made up of nineteen identical cubes, suspended high above your heads by some unseen force. Affixed to the ceiling are a pair of glowing orbs, lighting the configuration from above.

Around the perimeter of the room are thirteen closed doors. They appear to be identical but for the fact that each is labelled with a different word, carved into a small panel above the frame. Your party quickly notes them down:

TOMB, EYES, DARK, FATE, ONCE, FORT, BONE, DICE, LIFE, FIRE, WAND, LOCK, GOLD

Knowing that the wrong choice leads to certain death, through which door should your party attempt to exit?

Answer

The answer is

FATE

as pointed out,

Tearing the lights asunder causes them to swing to positions to the left and right upper sides. With light shining from those angles, the left light produces an image of F while the right light produces a boxy 8. Together, F + 8 = fate

Added info: To get the answer:

Imagine the lights are against the upper edges (left and right). Now consider the light passing diagonally through the shape, at 45°. From the left light, the far right upper blocks cast a line of shadow. The blocks closest the light also cast a line of shadow, a bit 'lower' than the first line. The blocks closest to us, the viewer, line up in such a way the no other shadows are cast, while the blocks farthest away cast a line of shadow perpendicular to the other lines, forming an F. Drawing this out helps a lot.

OP edit: here's a gif that might help visualise the above explanation:

Also note that the clue poem states:

you will 'hear' the answer - cuing to the sound of 'fate' rather than an exact spelling. nice touch.

Brilliant puzzle - used to love these kinds of tricks in D+D.