Comment by Nelson Mandela on Eternally Regressing Knight - Chapter 6

How did MC fail such a basic task? Just find a way to keep track of the exact moment, like when a certain gust of wind blows or wax drips that marks when it is certain the assassins have arrived, and then shout assassins one moment before that, and repeat until they don't respond to the shout to find the exact moment they arrive/get into position.