A funny comparison, nodnar. Well the spider / fly situation is an artificial mind created situation. We assign some intelligence to 2 creatures which they don't have. That what we call intelligence is primarily there to look behind the instincts we still have. To gain ego related benefits. But intelligence is not sufficient to get what we really are. The contrary is true since it cannot be understood by the mind where intelligence is usually situated. So I think if the fly would have got the needed knowledge / intelligence it would have said I take a nap and after 2 and a half minute I fly away...instincts still prevail at 'ordinary' flies and spiders. To do something on purpose there must be at least a body idea which most of the animals don't have (yet)...also the idea must be there to have (to recognize them as) own actions.
At one point I decided to do just that. So far it's been working just fine. Later I discovered that it's not all as I first imagined, so I may change my mind later and drop dead. You see, being immortal is not a same thing as being unharmable. Not all the injuries heal perfectly...