Method #1
Kill Russel by shooting the glass floor

Method #2
Kill Marcus by shooting the glass balcony

Method #3
Kill Russel and Marcus by driving the car out of the window

Method #4
Snipe Russel and Marcus without causing alert (Snipe them from the helipad below)

Method #5
Kill Marcus by posing as the pilot and crashing the helicopter, planting a C4 and blowing it up or stealing the buzzard from the helipad below and destroying it with the buzzard.




