- "A sitting duck"
- ―O'Reilly replied to the SWAT commander before shooting him in the head with his pistol at the annex skywalk [src]
O'Reilly was first seen marching at the hotel near the airport along with Colonel Stuart.
After Stuart took over the control tower's communications systems and instruments, O'Reilly, along with Sheldon, Shockley and Mulkey, were stationed at the annex skywalk at the new airport terminal (which was under construction), to make sure the airport's antenna ray was destroyed by a bomb. As Stuart predicted, the Airport's SWAT team arrived escorting Dulles communications engineer Leslie Barnes to the array. When Barnes and the SWAT team went to the moving skywalk, O'Reilly shut it off to provoke them. When the SWAT team leader angrily chastised his behavior while walking up to him, O'Reilly pulled out his pistol and killed the SWAT commander with a bullet to his head, springing the bottleneck ambush. Although Shockley was killed by a SWAT officer, he, along with Sheldon and Mulkey killed the last four SWAT officers.
O'Reilly crept quietly and held Barnes at gunpoint. Just when he was about to kill Barnes, John McClane kicked the vent cover open, distracting O'Reilly. O'Reilly looked up to see what was the matter, only for the vent cover to fall on his face, disorienting him. McClane seized the opportunity and he drew his Beretta 92FS pistol and fired at O'Reilly, hitting him three times in the chest, and thereby killed him. O'Reilly fell dead to the floor with three gunshot wounds, and a large vent on top of him. He was the second man in Stuart's group that McClane killed, and the third man lost during the operation.
In the deleted scene of Die Hard 2, O'Reilly killed two airport maintenance workers. He and Sheldon hid them in the airport van, when they used their uniforms to disguise themselves so as to watch over the Annex skywalk.