Assassin's Creed 3 Walkthrough Part 34 – Sequence 6: Hostile Negotiations – The Kill

Optional Objective:
Kill Johnson before a single Native American is killed

This second optional objective is given the moment the cutscene ends. Time is of the essence and very tight. Start running for the edge of the cliff that lines up with the nearby trees. Connor needs to jump from the cliff, through the trees to the roof of the house. Once on the roof, head to the left and get to the edge of it. Look down and target Johnson. From there immediately launch your attack on Johnson.

Optional Objective:
Perform a Swan Dive to escape

Once the scene with Johnson ends it is time to start running and fast. Sprint down the slope in front of Connor. Do not bother fighting any of the soldiers as they can simply kill you and bring about a different ending here. Just run forward and to the left. You need to weave your way through a few of the guards (possible killing them). Run up and over the ledges to find the one branch reaching out over the area. It is from here you can perform the swan dive.

Once you land in the water swim over to the reeds. It is a simple matter of waiting then to finish the mission and complete the memory sequence.