Do you keep all of the memories up until the moment you are at -10 HP?
My thought is that an assassin would have to render you not only dead but keep you that way for the 3 day period to which you become unraisable.
The three-day thing is typically an OOC piece of knowledge, as not even those who are most gifted and knowledgeable about the planes and the Cosmology in general wouldn't know about the handling of souls, unless some Heavenly messenger spelled it out for someone.
well, when I was discussing it with Ed he seemed to think the 3 day thing was a known thing - maybe a cleric would not know WHY after a period of time a body becomes unraisable - the concept of soul strands and the like not a tangible piece of knowledge, but the time frame could be. Clerics with the ability to raise the fallen would afterall be a fairly uncommon thing in the ranks of local or common clergy ...