In an open war between two nuclear powers, the first to strike with nukes is far more likely to win. Especially true when one or both sides doesnt have the means to strike back if successfully decapitated by nukes. To make matters worse, they are imbalanced; India has nuclear submarines that could respond if Pakistan launched a preemptive strike – Pakistan does not. That means India has a high chance of pulling off a successful 1st strike. I think the odds that India launches a preemptive strike if things escalate or higher than anyone wants to admit. Pakistan would be foolish to launch a first strike themselves, but then again they are just as aware that a 1st strike may be the only strike they have a chance at, at all. If they wait to be nuked first, they may be destroyed without retaliation.