We have radars that cover not only our airspace but also airspace of our neighboring countries. So if a bogey is vectoring i.e if an unidentified aircraft is making a move towards your border you can scramble you jets towards the border where these bogies are expected to breach your airspace.
So your reaction time does not start from the time some one is already in your airspace!!! rather it starts when the radar operator identifies prospective airspace violation!! any reaction to this depends on your state of alertness and policy towards such incidents.
Seems like either there was no radar coverage or the guy at the radar was asleep or there where no orders to protect airspace from unidentified intrusions!!!
dont worry itna serious scrutiny kurnae kee keeya zaroorut, we r in good expert hands of PAF, no tension(bigsmile)