Despite her reputation as a mass murderer due to corrupt, Communist-like courts during the time of the French Revolution, grandmama La Guillotine herself is actually a kindly old woman, who wants only to minimise the suffering of her users, by making their severing experience mercifully short.
 
Only to be used when there is no hope of curing the ailments of the body. Ideally, one should have a jar on hand with appropriate life-support connections prior to making the chop - better to be prepared beforehand than to realise too late one is short a connecting wire.