OK, so armless man severs his own arm. He sends it to man 1 and instructs him to send it along to man 2. But man 2 is not instructed to bury it? There is nothing in the solution that tells me man 2 was instructed to bury it.
Have I got that right? Yes
Did man 2 just bury it of his own free will then? That's how I read it. I don't see anything special in the act of burying the arm, except that stinky mess thing. :p
Did anything relevant happen between when man 1 got the arm and when he sent it to man 2? No
Did anything relevant happen between when man 2 got the arm and when he buried it? No
I admit I'm completely stumped at this point. But you're off in bed, so I'll do something else and think upon it a while Well, as usual, I'm awake for a while now.