After the part where Niobe and Ghost make phone calls, you will start the level on top of a balcony. You will receive a message from Spark warning you that SWAT members are approaching. Do not bother with the stairs, and jump the railing down to the first floor. Directly in front of you are SWAT members coming through two sliding doors. Run past them while shooting and go through the sliding doors, then run behind the SWAT van. There will be a entry shotgun here.