Method primitive Guillotine

[Bufo]

What do you think of this method?
Knot a heavy stone to a rope, pull it up over a high tree branch, lie the neck underneith and let the rope go so that the rock smashes the neck.
It seems painless, safe and easy to me. Just Survival instincts worry me.

 

[Praestat_Mori]

Unreliable. The stone has to be very heavy, you may not keep your head/neck in place, you might end up severely injured. When the stone indeed smashed your head/neck, certainly relatively quick/painless but it's better to be decapitated, that's what a real guillotine usually does.