Underground worker might mean a number of things. In my youth I considered myself as somewhat of a Hippie. Back then Hippies were considered part of an "underground movement" by some, but I wasn't really that serious of a Hippie--I just identified with the movement to a degree. A small degree. It was pretense mostly. I wasn't really very underground back then other than when I was exploring caves. Being claustrophobic as I am, caving wasn't too much in my comfort realm. I stopped doing that after a while. Being underground isn't so much my thing.
When I was a kid living in San Diego. during our frequent visits to Tijuana Mexico I would see many shops advertising "tuck and roll upholstery for automobiles". There were a ton of those places back then, but I was never lured by the world of upholsterers. When I had furniture that needed to be upholstered I just got rid of it and bought new furniture. I'm no upholsterer.
Undertaker seems like a very bizarre job to do. Sure, it's respectable and can be lucrative I suppose, but being around dead bodies in a very intimate way seems creepy to me. Somebody's got to do it, but that person is not me.
Neither is United States Government worker. We've already got too many of them anyway. If I had spent my life as a government worker, I probably would be enjoying a better retirement than I do now. That is, if I had survived the work. I'm sure there's a lot of government jobs that could have suited me, I didn't do them or pursue them. So much for government work.
Were you ever involved in underground work in reality or metaphorically? Have you ever had anything upholstered or done it yourself? Did you do any work for a government?