- Lockpick four doors
- Drive two Brutes berserk
Sticking to the rooftops, make your way around to the northeast corner of the building. You have to watch out for some Extremists who are guarding the area, but you should see two open windows that you can use to sneak into the building.
As soon as you're inside, you'll want to take cover along the west wall of the room you're in, using your Eagle Vision to spot three guards in the next room. When one Extremist eventually walks by the door, perform a kill from cover to take him out. Next, sneak behind the dude at the desk and kill him, then do the same thing to the one looking out the window.
Backtrack into the room where you started, approaching the locked door and picking it to complete part one of this four part challenge. Don't bother going through it, instead continuing to head west until you reach a room with a hiding spot, taking note of two Brutes in the room further along. When the coast is clear, sneak behind the Brutes and score silent kills.
The double door that sits along the west wall is the one that leads to Germain, but before you open it you'll want to pick the nearby locked door, completing the second of this four part challenge. Don't forget to snag the Artifact off the wall, then open a third locked door that sits on the opposite side of the room. Be careful not to get spotted by an Extremist, then backtrack to the white double doors, going inside and triggering a cut scene with the man you're here to see.
Kill the Thugs
Following the cut scene with Germain, you're going to need to clear a path to get him out of the compound safely. Start by taking cover next to the door with the three bad guys outside, using your Eagle Vision to time a silent attack on the two who hang out on the right side. With them down, move up and take out the third Extremist who stands near the window.
Loot the three dead bodies and then move up, taking cover at the top of the stairs. This is where you want to start working on your challenge to drive two Brutes berserk, taking out your Berserk Blades and targeting the Brute by the window below. The remaining Extremists will attack him, but this guy is quite tough and will do some serious damage. Let him work for a moment, seeing how many of your foes he can take out. You can deal with whatever remains using your Phantom Blades, or some fantastic sword play. As always, make sure to loot all the bodies, but then continue making your way forward until you spot an Extremist in the next room.
Speed is of the essence in this part. As soon as you spot him, the lone Extremist in the next room will start to walk away from you. Quickly sneak behind him and perform a silent kill, then move up and take out the Brute and Extremist standing at the desk. This is most easily done if you have the Double Assassination skill, but either way you want to move quickly. If you wait, the three guards will scatter and make it difficult to remain undetected.
While you could go forward another two rooms to the next set of enemies, move into the side room next to the desk and pick the lock on the nearby door. This will complete the challenge requiring you to pick the locks on four doors.
Two rooms ahead of where you took out the two adversaries a moment ago will be a room with four more, including at least one Brute. Take out your Berserker Blades, then shoot the Brute to complete this challenge. Just like before, let these fools kill each other for a moment, but don't hesitate to hit them with some Phantom Blades from afar. When the room is clear, move into it, but don't take the front door to get outside, instead going through the door on the left side.
You should now see two objective markers that point to Extremists on balconies. Move into a flanking position, then take them out with Air Assassinations. When this is done, return to Germain and kill his attackers to complete the memory.