unconscious violinista famous unconscious violinist. (Lets call him Mr. K.)

unconscious violinista famous unconscious violinist. (Lets call him Mr. K.) He has been found to have a fatal kidney ailment, and the Society of Music Lovers has canvassed all the available medical records and found that you alone have the right blood type to help. They have therefore kidnapped you, and last night Mr. Ks circulatory system was plugged into yours, so that your kidneys can be used to extract poisons from his blood as well as your own. The director of the hospital now tells you, Look, were sorry the Society of Music Lovers did this to youwe would never have permitted it if we had known. But still, they did it, and Mr. K is now plugged into you. To unplug you would be to kill him. But never mind, its only for nine months. By then he will have recovered from his ailment, and can safely be unplugged from you. Is it morally incumbent on you to accede to this situation? No doubt it would be very nice of you if you did; it would be a great kindness. But do you have the moral obligation to accede to it? (What if it were not 9 months, but 9 years? Or even longer?) [MO1, 2]