The Hidden Blade Assassin's Creed in Depth

This is the first story assassination in Assassins Creed Mirage.

Infiltration

There are at least a few ways to get inside the area. One of them is a climbing section on the target's side of the place, giving you easy access to where Al-Ghul is waiting behind a locked door. Through the door screen you can target him with knives but are unable to cause any damage. Being in open conflict can cause the target to engage you in combat, but even that is a fruitless attempt to interact with him before the actual assassination.

Earliest Possible Assassination

I loaded a manual save at a part where Basim is almost at a checkpoint allowing you start the assassination (you are unable to save inside a restricted area, so did that outside). Pre assassinated some guards in the area top make things easier. I just need to talk to an NPC to lure out the target. After a short while Al-Ghul teleports through the door, giving you plenty of time to lie in wait for an instant kill. Ubisoft didn't anticipate players to do this, like an assassin actually would. One interesting thing to note is that sometimes the memory corridor doesn't load right away like normal.