Between The Devil Challenge Glitched???

So im trying to do all of the challenges on the Pen And The Sword mission in sniper assassin and currently on the between the devil Feat but I'm really stuck. I have Jin Noo in his office but when i shot the siren on the highest point of the boat nothing happens. I have tried spam shooting it and have also tried to shot it and wait for the sound to end and then shot it again but he just won't leave?