When you are trying to kill general Aziz at the end, take out the "laser" and lock on so it turns red. He will run out. Take him out with a sniper, then evacuate.

When you call in an artillery strike on General Aziz's underground bunker, an alarm will alert the town. General Aziz will then run out of the bunker. You have to shoot him before he escapes.

Connors is recommended for this trick. Have one of the others off to the side, near the exit to your extraction area. Have Connors directly in front of the doors to Aziz's bunker, but back as far as he can be from the doors. Have your first squad member "lase" the bunker for the airstrike, then switch to Connors before the doors to the bunker open. As soon as the doors open, have Connors open up on Aziz and his two guards with either a machine gun, or have him launch a RPG/rocket into the bunker.