In the game Assassin's Creed for the Xbox 360, in the memory block 4 one of the informers from the rich district of Damascus will give you a mission to assassinate two guards in less than three minutes.
It must be done as a stealth kill, that is, no witnesses (or at least not witnessed by guards). But the NPCs I must kill only wander on streets full of guards.
I don't get a single moment with the white icon indicating I'm unnoticed. If I try using the hidden blade while the icon is yellow, the mission fails. If I try to throw a knife from a certain distance I am imediatelly noticed.
I tried to follow this video(see @ 8:10) but after killing the targets I immediately become discovered and the mission fails.
How do I complete this mission?