How do you beat hideout in sniper assassin 3

Hideout is mission 7 in Sniper Assassin 3. You kill one guard by dropping a tower on him, but the other 5 have to be killed in a certain order so that they can't sound the alarm.

Besides the three guards on the roof, there is one walking along a balcony, one behind a window, and one standing at the left. First shoot the rooftop pipe between the left and center guards, which will block their view with a green cloud. Then shoot one of the guywires on the tower at right (don't shoot the second one yet). Now you are ready to kill the six guards.
The guards: Shoot #1 in the window. Once the patrolling guard is headed right, you can shoot #2, the lone guy on his left. Then, when he turns back left again, you can kill the three roof guards. Guard #3 gets killed when you shoot the second wire, dropping the tower. Quickly kill #4, the middle roof guard, who comes over to investigate. Shoot #5, the left roof guard, then #6 , who is still walking back and forth.