A detailed analysis of the case of the hit on the drowning man (situation one) shows that though it involves the use of force without the prior consent of the person on whom it is exerted, the force used is ultimately used with the motive of saving the man’s life. The situation includes the application of force without the consent of the man against whom it is used: and in this sense, it may be said to be a case of violence: but the force is used for the good of the drowning man and not with any desire to inflict injury or harm to him; and in that sense, it may also be said that it is not a case of violence. In these special senses, the situation can be said to involve violence and non-violence respectively; but in the ordinary sense of the words, it cannot be looked upon as a case either of violence or non-violence.
The case of the operation for the cure of contagious disease (situation two) is slightly different from the case of the drowning man. Here also there is application of force (amounting even to the cutting of the affected part of the body); and the application of force is for the good of the person against whom it is used: but in most cases of such operations, the patient gives his prior consent for the application of such force as may be necessary for the execution of the operation. Further, the operation is intended not only to protect the patient himself from the further ravages of the disease, but is also intended to protect others from the spread of infection. The application of force here springs out of the motive of doing unmixed good, both to the patient as well as many others who might come into contact with him. Since no harm or injury is intended, the application of force in this situation does not amount to violence, in the ordinary sense: and it also cannot be adequately looked upon as non-violence, since it is a clear case of cutting a part of a living body.
–www.lordmeher.org,p2780