Just like towards the end of the first mission, you will have to keep in mind that capturing Nouri includes several serious handicaps. Fisher can't leave the captured person, he can't use melee attacks and, if detected, he will draw reinforcements onto himself. There are upsides too - unlike in the case of escorting Kobin, this time you won't have to eliminate anyone on your way to the docks. Go down the path and take the first turn to the left, into the passage between rocks shown in the screenshot.
Stop where the rocks to the right end and wait for the enemy, who is patrolling the area to the right of Fisher goes towards the exit from the estate, where you have started your march towards the docks. Turn slightly to the left and go through the only available passage to the next location.
Stop again when you reach the rocks. You need to wait for one of the assailants to go to the right AND the other enemy, shown in the screenshot, stops in the spot shown in the screenshot. Only then, move quickly towards the water, while keeping the necessary distance to prevent being heard.
The final part of the march will not surprise you with anything new. Keep moving close to water and go towards the buildings to the left, because this is where the motorboat, which you need to use, has been moored. This mission will soon draw to an end.
Perform all of the standard actions in the mobile command center, i.e. talk to the allies and make purchases. After you have dealt with all your business here, interact with the SMI and select the optional, or the main mission - Abandoned Mill.