Escape?
There is no escape.
Sometimes one or two people sneak out. But they have know that everyone they knew is now dead because they left.
You get shot on attempt. Trying to leave up North? If the border control doesn't shoot you down, the mountains will kill you. Trying to leave down South? If you get through the electric fence, through the patrol, and the dozens of miles full of land mines, then the South Korean border control will shoot you instead.
one of only known survivor of North Korea was Kim Jong's sushi chef
he escaped after convincing Kim Jong Li to let him go on an expedition to get sea urchins from Japan
(to make a special sea urchin sushi)
now he's in hiding in Japan
but even Japan isn't safe because North Korean agents are allowed to be there