Theoratically, what will happen if India , is on the verge of a military victory in Pakistan. Indian tanks are rolling into Islamabad. The state of Pakistan as we know it , is seriously in danger of being annexed. The Indian defence minister , says that once Islamabad is captured, Pakistan will no longer exist and will be divided into 4 states.
Somewhere near Kahuta, Seniior officers of the Pakistan has about 80-100 nuclear tipped missiles , they have a choice to make ? Do thay risk a nuclear war , by launching missiles targetting Indian cities , or do they destroy those missiles, so that they cannot be used by Indians ??
Well its Pakistans official doctrine to use nukes in such a scenario.
In the scenario u mentioned , I think Pakistan would prefer to use tactical nukes on Indian troops inside its territory. saadahmed has rightly said 'The generals who will be launching missiles also have families.'
I read two novels by Humphrey Hawksley 'DragonFire' and 'Third World War'
The first deals with Asia at war, while the other deals with World at War.
In the first novel when India had penetrated deep inside Pakistan, tactical nukes were used against Indian soldiers.