Execute the guard then continue upstairs. Take out another guard there then plant the charge at the back of the trailer truck. Stand by then kill the guard when Mother tells you so. Next, stand behind the barricade to detonate the truck.
After detonating, you have to head to the extraction point. All hell breaks loose but you'll still need to keep an eye off enemies that you'll encounter along the way. Follow Mother as you make your way through the containers until eventually, a hostile armed helicopter halts your advance. Pick up one of the SMAW launchers near the railings then take the helicopter out.