Dan Dennett's Intuition pumps

Akrasia

Daniel Dennett has just released a new book 'Intuition Pumps and other tools for thinking'

Dennett has developed the idea of intuition pumps as 'thought experiments' using analogy to stimulate our intuition and explore complex ideas, his spin on this ancient strategy is that intuition pumps can be productive, but they can also stifle your imagination. if your thought experiment includes elements that restrict your imagination he calls them BoomCrutches (silly name but if you read the book you'll understand). BoomCrutches are defective intuition pumps, leading arguments that seem like they are stimulating arguments, but are really just stoking existing prejudices.

After reading the book I found myself thinking about creating my own intuition pumps on difficult philosophical problems

Dennett is an atheist, as am I, and one of the main issues for atheists is morality and how we define right or wrong.

Is it wrong to kill another human?
Thou shalt not kill doesn't apply to atheists, we need to think about the reasons why killing may be acceptable or unacceptable

Personally, it is wrong to kill not because the act itself is wrong, but because of the consequences of the act. Killing someone harms both the person who dies, and their family/friends/economic interests and it is wrong for me to cause such harm to others.

In certain circumstances, is it right to kill? Euthanasia for example?

Assuming the person is at the end of his/her natural life and is facing suffering and pain. If that person asks me to help him/her end his/her life with dignity, I would feel that is a morally good act.

However, using intuition pumps, can we test this intuition?

Here's what I have come up with
Imagine the film Castaway
We have the main character, he is stuck on an island, he is presumed dead by all his friends and family and economic interests. He is feeling suicidal and he even attempts suicide.
He wants to kill himself but he hasn't got a strong enough rope to hold his own weight.

Imagine i am on a different island where I am equally as isolated and trapped as he is and I receive a message in a bottle where he explains his situation and declares he wishes he has a strong rope to kill himself. There is no way I can get to his island and rescue him or help him, but I do have a strong rope and I can put it on a small raft and send it out to sea on a current that might reach his island, should I send it?

What about if I don't have a rope, but I have an old Korean war Mortar which can reach his island, and he has provided the coordinates of where he sleeps at night. I can fire one shell that will land on him while he is asleep and end his life painlessly.

The reason this is interesting to me, is that we have seen this movie and

he survives and is rescued

But at the point in the story, we have a man who wants to die, he is a hermit and his death will not have any effect on his loved ones or economic interests because they think he is already dead
At this point, the chances of him getting rescued are very remote, the likelyhood he will die of infection or in an accident are very high. If he had happened to have had a strong rope, he would already have killed himself.

Without knowing the end of the story, at point x, what are the atheistic reasons why intervening in this situation is wrong?

Or is this not a valid intuition pump, have i actually created a BoomCrutch?