Dissatisfied with the level of comfort, he starts designing and building improvements. After a while, Hell has air conditioning, iced water, flush toilets and escalators, and the engineer is a pretty popular guy.
One day God calls and asks Satan,
"So, how are things going down there?"
Satan says, why, things are going great. We've now got air conditioning, iced water, flush toilets and escalators, and there's no telling what this Engineer is going to come up with next."
God is horrified. "What? You've got an Engineer? That's clearly a mistake – he should never have gone down there! You know all Engineers go to Heaven. Send him up here immediately!
"Satan says, "No way, I really like having an Engineer on the staff. I'm keeping him."
God says, "Send him back up here or I'll sue you."
"Yeah, right," Satan laughs, "and where are you going to get a Lawyer?"