How do you beat level 3 on causality

There are 6 victims to kill.
1) As the sentry on the left side walks forward, click the searchlight at the right so he stumbles into the fuel barrels. When he goes back up the way he came, click the stack of barrels, which fall on him.
2) A jeep drives up to the checkpoint. As it goes through, click the wire that leads to the raised bar, so that it falls on the headlights, and the jeep drives into the fuel barrel, exploding.
3) Two guys come out to see what is happening. Click the one on the right and he drops his gun. Then click the stack of crates next to the tower, which makes them think there is an attack. One throws a grenade that blasts the base of the tower, killing all three.