The history of humanity has been a history of doing stupid things, and hoping they work out for the best. From the first moment a bipedal ape looked across a chasm, and thought that they could totally make the jump (spoiler: they could not), humans and their antecedents have, from time-to-benighted-time been taking the ill-advised course of action, even in the face of all the evidence that they really shouldn't push that button.
No matter how intelligent, educated, skilled, or devout a person may be, there is always that little voice that says, "What if you did though?" And there is always someone, no matter how intelligent, educated, skilled, or devout, who listens.
It is this voice that speaks in the ear of a man in black as he regards an artefact of ancient Terra, a daemonic thing crafted of flesh and staring eyes, with no little sense of desperation. It is a box, he has just realised, and not merely a cube. A thing that could be opened and looked into, and perhaps extracted from… if only he knows the right twists of the Warp.
Whatever is inside could save this planet, or damn it.
He shouldn't. He manifestly should not; he has no way of knowing what lies within, and for all his psychic might, he is but one man. He knows better, even with all the forces of Chaos bearing down on this world, knows better than to use Chaos to fight Chaos.
"But," whispers that little voice that lives in all of us. The voice of curiosity, the drive and desire to know, to try, to strive. The voice of desperation, the voice of need, the drive and desire to do something, anything-- "What if you did? Surely," that part of himself continues, as he regards the box, "Just a peek would hurt nothing? This world is lost; what more can you lose, just by taking a look?"
There is a list of reasons longer than he is tall why he should, in fact, not. On any other day, he would listen to them. On any other day, But today, a thumb tips the scales of Chaos. The man gives in to the sins of both curiosity, and desperation, and opens the box.
Just a peek, he tells himself. "To see if it can be used."
Just a peek is all you need to finally, finally escape.
The Prison Realm is a place of utter isolation. It is meant to drive those contained within it to madness, despair, utter senselessness, and finally, after an eternity of nothing, death. If you were a lesser man, that would certainly have been your fate. But you are not a lesser man, you are Gojo Satoru, alone honoured in heaven and earth, and there was no way that you were going to let that thing get to you.
It was a very ambitious resolution; too ambitious perhaps, even for you, because although you dedicated a portion of your formidable mind to keeping the time—second by second, as you lay in a heap of bones, the remains of you predecessors—after a time it had seemed to you that you must have missed something. Skipped some vital moment, blinked, lost count, something—because the count of seconds made no sense.
It made less sense as time dragged on, as you devoted another portion of your kind to theoretical applications of your technique—all you could do with it, until you could get out of there.
Thinking.
Counting.
Thinking.
Counting.
Endlessly, thinking and counting and thinking and counting—
You understood how a lesser man could be driven mad. You could be driven mad by the sheer lack of stimulation—the only end to the nothingness was yourself, and the bones.
You had counted all of them by the time the way out opened up.
You knew yourself excruciatingly well, right down to the last quark by the time something shifted, and the changeless near-void cracked.
That slightest crack is all you need to be free.
As you pass through the space between the Prison Realm and the outside world, everything around you dissolves into endlessly shifting fractals. The tiniest permutations of cursed energy are like brilliant flares in your sight after so long blinded, and the world blooms around you in brilliant colours--some invisible to anyone else--smells--all of them horrifying, after so long smelling nothing but bone, dust, and your own skin--and sounds--an electric hum, and the beating of another heart.
Before you stands a man, armed, armoured, and clad in black. To your immense surprise, he is actually taller than you (you straighten your spine a little at the realisation, to no avail); you can count on your hands the number of times you have met someone taller, and still have fingers left over. This man, with his short-cropped hair, pale skin, and brown eyes makes eight. Seeing the shape of his cursed energy, you know him for a sorcerer, which makes him the second. (That time in second year when Suguru was one centimetre taller for an entire month doesn't count.)
By the energy you can see and the vectors you can sense you know that you are not in Japan. You are, in fact, so far away from Japan that although you can comprehend it--you cannot help but comprehend it, with your technique--a very large part of you wants to wholly reject it.
Regretfully, you don't have time for that, or for the breakdown that you really deserve to have, with all this sensory input after--you don't want to think about how long. Too long. Everyone and everything you have ever known are dead and dust, and you really don't have time to think about it. You can see the energy of curses, thousands of them, bearing down on this location, and you cannot see any other sorcerers save this man, and yourself.
The curses are accellerating, no doubt drawn by your sudden presence. You have time, though. Time before they arrive to assess yourself, and prepare.