It still sounds like suicide by garbage truck to me, and not a great way to go either. A great many people in organized crime seem to own landfills and garbage companies, and people disappear all the time, a landfill probably a great place to dispose of an unwanted body. Surviving the truck with a seriously mangled body (trauma, many broken bones, punctured lung, ect...) sounds like the first hurdle, the dumping out of the truck at the landfill the second part.
I imagine a lot of the dumping happens at night, and looking for bodies living and otherwise might not be a high priority for the employees. Do they even dump right on the mountain of trash directly, or does it go through some kind of shredder first, to remove the bags and other things before getting plowed under by those huge machines?
I had a teen job in a shopping mall back in the day, and one of the jobs that I had was to take the cardboard boxes out to the box crusher. It was a machine that crushed the boxes into a huge dumpster that I assumed they picked up every few days as it was a big mall. Sometimes other things made it in there too, and it crushed them flat, no effort at all. That machine was relatively slow and benign as to compared to a garbage truck, and generally speaking clean, but I still doubt a human could survive getting crushed up in even that.
Not that I advocate doing anything illegal or anything, but if you want to have some fun, buy an old mannequin at a "going out of business" department store. Handcuff it, bind it with ropes, duct tape, plastic bag over its head, dress it even, be creative; anyway, put it in the garbage and wait to see if it pops up on the five o'clock news. See the "found" condition of it, I'll bet it's destroyed. Cut it open beforehand and place some zip lock bags full of red fruit juice inside, to maybe get some idea of what kind of force is involved, if they show the picture, if they even notice it.
Life is short, play safe, Jackie.