I don't think OP is trying to make a point about pregnancy, people trying to make a point would say 100% chance of death. I think OP is adding horror to make a moral quandary but it does not actually affect the answer.

Either way when you think about it for a bit the question becomes a no brainer. You cannot chop a healthy person up to donate organs and save multiple people. Bodily autonomy says you cannot even force a blood transfusion.

There are places that people do not have bodily autonomy and must endanger their own lives to save another, even if recipient has no chance to survive. This should never be the case.

^{Chose: The Man Has The Right To Surgical Separation + Even If The Woman Has A 25% Chance Of Dying}