The Hidden Blade Assassin's Creed in Depth

Assassins Creed Unity la Touch Unique Kill

Ultrablend

It helped to use the Ultrablend Exploit, found by THB member Altair Auditore.
http://thehiddenblade.com/ghost-paris-glitch-aka-ultrablending

Unique Cinematic Scene Kill

After hearing complaints of there being only one optional cinematic scene kill in the game, I set out to create another one. The "unique kill" scene in sequence eleven assassination happens to work for it (tried for others, but you don't get enough time to start assassinating when you activate the scene).

Using Ultrablend, you don't have to worry about all the guards in the area. Perform an action that makes guards detect you, causing la Touche to flee.

After the target reaches his waypoint, the fleeing AI is replaced with normal combat AI. Tackle him, and in combat use staggering strike to move him to the caged area. Now steal the key. To get a "scene kill", tap in rapid succession. If you're fast enough, the scene will start right after the kill animation starts.

After the memory corridor, the cutscene cancels. This results in objects appearing blurry unless they are right in front of the camera. Another glitch from this I didn't bother recording: losing all your health results in the memory completed instead of desynching.