I left the temporary hell assignment for a promotion to a new permanent job to the shop taking over the work permanently.
The boss of the temporary hell assignment was just made the new boss of the permanent shop.
My escape plan turned out to be a circle. It was a risk to escape into a job so close in the org chart. I figured out the flaw in my escape plan: They offered me more money to work in the same chain of command, and I said yes. Damn them. Damn them to the Special Hell.