Race for the Prize

Of interest to the editor:

A friend posed this to me the other day. Imagine that there is a runaway trolley, and this trolley is headed down a track toward a group of people, you have the power to flip a switch and divert the trolley down a different track to where one person is having a picnic, killing that one person but saving the others. Which do you choose?
I chose to switch the switch because someone is going to die no matter what so it's better to save the lives that I can rather than save one life and kill the other people.
So then my friend posed the second scenario. You are a doctor and have a number of patients who need transplants, one needs a new heart, another needs skin, another needs blood type O, another needs a bone marrow transplant. In walks a man with all the specific body parts that are totally compatible for the patients. Your fellow hospital doctors say that you have to kill him to get his organs and save the lives of all these others. Do you kill him? There is not much time left so it's either kill this perfectly healthy guy who's a match for all these other people and save their lives or let that guy live and watch the other people die.
I said no, I don't kill him because killing another man is wrong even though that means all the patients will die.
So what's the difference between the first scenario and the second scenario? Basically, you aren't the trolley. For some reason people find it more ethical to switch the trolley's track killing one person than to actively choose to kill one person to save others even though killing one person in both scenario saves more people. If the choices only include either killing one person or killing a few people, we defer to the quantity to choose which is ethical. If there is an option to kill one person to save others or not kill that one person, not killing that one person becomes the most ethical choice. In the doctor scenario you could kill one person to save others but it seems wrong because you are actually doing the killing. Because there is no option to choose to kill like there is in the doctor case, switching the track to kill one person seems ethical even though the death of one person saves others just like the doctor case.

Daniel