Poor Urist had no idea what was happening to him. He had fallen asleep by the wagon, bundled up under his pigtail cloak in a pile of snow. He had been drinking last night, that much was for sure. Someone was playing a cruel joke he thought. His cloak was damp, probably with snow, and someone kept lightly shoving it. Rakust wanted him to go brew another batch, but Rakust would have to wait.
Oy. Quit it, he mumbled. But the shoves continued. He rolled over.
Oy stop it I'm awake, he moaned, still under his cloak.
What was that awful smell. He knew that smell from the mountain home. It was blood. Not dwarven blood, and not quite fresh, actually it was a little off, but it probably meant that dinner was up.
Urist jumped out from under his cloak, hoping to beat the crowds to the dining hall.
And then he saw it. It. It wasn't Rakust, it was a giant towering man made entirely of blood. A... Blood Man.
Urist ran. He ran and ran, through the endless glacier. He prayed, not to Armok, knowing Armok would probably favor a man made entirely of blood over himself, but to his own god of murder and loving kindness.
Urist glanced over his shoulder. The blood man was no longer chasing him. It had slowed to a stop several paces behind him.
And then the Awesome occured.
The Blood Man's left hand froze solid, and fell to the ground, a pile of frozen corrupted blood. Then his right hand. Finally his head.
This gave Urist an idea for Dwarven Science.
*Spoilers Below*
Question: What happens when demons are released onto a glacier?
Answer: Fire/Flame demons melt all the snow, slaughter all the wildlife, and your fps is cut in half.
But that's not the science... The science is this: If you release demons into a cavern in reach of your dwarves, your fps drops like mad (dropped to 16 from 150ish). However, if you release them into a staircase running straight up to the surface with no cavern access, and no access to your dwarves, your fps does not take as large a hit. (dropped to 80 from 150ish)
Thus begins the real science. I hypothesize that the reason opening hell is slow is because all the demons released to begin with are fliers. I believe that keeping them in a relatively small enclosed area will not cause anywhere near as much of a performance hit as giving them free reign over the caverns. Further, I hypothesize that very large open rectangular spaces with no obstacles (aka the open space above ground) are far less painful than caverns.