Buddy, remember that this was happening at night, past midnight in fact, so it must have been pitch dark. They could obviously not use illumination to assist in the firing. In these circumstances they had to wait for the terrorists to come close so that maximum casualty could be inflicted on them. The 'see the whites of the eyes' is just a figure of speech, an ambush waits for the enemy to come into the killing ground, the weapons are sited to cover the killing ground effectively. How far the killing ground will be depends on the visibility. In day time, it may even be 200M to 300 M away, at night......maybe 100 M. In uneven and rugged terrain, maybe even nearer.
Sniper course has very few vacancies, the ghataks may attend a unit level sniper cadre which is not the same thing. But snipers are not ideal weapons for night time ambushes where you want to totally overwhelm the enemy with a heavy volume of aimed fire.
They could have used their skills to eliminate the terrorists with suppresed weapons from longer distances.
How? when you cant see a man at long range at night without illumination, how do you engage him? After the fire fight, all you would find is that the enemy has got away clean by taking cover in the undergrowth and in the folds of the ground. You would be lucky to find the odd blood stains on the grass signifying a possible casualty. Then you would chase him, but in which direction? remember, the terrorists are also trained in camouflage and concealment, he would not present himself as a target till he is real close. The tactics of the terrorists are very sound.
All said and done, Lt Navdeep was bang on the money. There is no way to ensure max kills in a night ambush unless the enemy is allowed to come up close. The only problem with letting the enemy come close is that the ambush party itself becomes vulnerable if they charge at it. These ghataks knew all this. They knew the risk. Long range firing at the terrorists at night without illumination in rugged terrain would have been ineffective. An opportunity lost.
Regards.