Optional missions assigned by Kobin | Mission 12 - Site F Splinter Cell: Blacklist Guide

You get access to the additional missions from Kobin only after the first mission, from the main campaign mode, is completed, i.e. after you capture him. You can select them in two different ways - by selecting the appropriate dialogue option during the conversation with the captive Kobin, or by choosing the appropriate category on the World Map. The characteristic feature of these missions is the stress on remaining in hiding because, causing the alarm to be raised results in the appearance of the enemy reinforcements in the area which, for obvious reasons, makes progression more difficult. The premises for each of the Kobin's missions are the same and they assume knocking down, or murdering, all of the hostiles in the location.

I recommend that you take on the missions of this category after you gain upgrades that facilitate avoiding of the enemies (the radar, the elements of the suit that suppress Fisher's movements etc.). When it comes to the gadgets, select only the ones that allow for quiet and easy takedowns (e.g. crossbow with sleeping bolts, sleeping gas grenades, proximity mines) or kill the enemies (suppressed pistol and sniper rifle).