Right now, non-hypothetically, would you be willing to donate your internal organs to those who will die without them, even if it meant you will not survive yourself?
Jokes aside, I'm aware of my own moral weakness in this regard. The religion I was raised in - and I'm still a spiritual person - holds that suicide is the gravest of sins, but I don't have that high an opinion of my own life and its potential. The closer I am to the situation, and the more urgent it is, the more tempted I am. So I try to stay aloof, for the sake of those who love me, and out of my own instinct of self-preservation, which is a powerful force in most human beings.
If your mind was exactly like mine, and you were close enough to the situation to make the decision to sacrifice someone else for a group of strangers - and being tied to the tracks is pretty damn close - you would likely be willing to sacrifice yourself. But remember, someone must have tied me to the tracks in the first place for my life to be in danger. As I said in previous comments, in most cases I am, though inaction or stalling, attempting to save the life of the single person in the tracks - the person in the same position. I will not kill to save others, and attempting to not kill myself to save others is consistent with this position.
I would be useless as a soldier!
For instance:
- Being run over by a trolley is a highly improbable event
- Being run over by a vehicle (higher category in which trolleys are a part of) is a less improbable event
- Dying of a very specific form of cancer which destroyed an organ is a highly improbable event
- Dying of cancer is less improbable
In the scenario for organ donation, what if the recipient had an improbable reason for needing the organ?
As far as my own views, I don't know if the tragicness/one-offness/improbability of the cause of death factors much in my decision-making. Though, I do think there's probably a good argument for reducing active suffering (that I haven't fully thought out).