Monroe was first seen in the Crisis Room at the Pentagon during the White House Siege. General Edward Clegg, the U.S Army Chief of Staff, tells everyone to get the Rapid Response Team from Andrews Air Force Base moving. General Clegg asked Monroe how bad it is. Monroe tells the general that the front fence has been breached, as well as the crashed C-130 Hercules burning on the South Lawn and the gunfight raging on the North Lawn. Sometime after Speaker Trumbull entered the room, Monroe reported there was contact inside the White House and the confirmed trace was the President's sat-phone. Trumbull asked Monroe to put it through. Trumbull asked if it was the President but sadly not. He asked the responder to identify himself and he responded he was Mike Banning. Monroe wanted to verify with Trumbull and Jacobs if Banning was the same guy who was removed from the president's detail after the accident where the Americans lost the First Lady. He also asked how can they trust Banning but Jacobs convinced Trumbull to do so. With no other choice, Monroe and the others trusted Banning and listened to his report that commandos were roaming the hallways "with enough explosives to take out an army", the doors and windows were rigged with C4 explosives, and the terrorists shut the power down and closed the air vents. Banning also reports that he shut down the surveillance for a brief period of time. Banning informed the terrorists are looking for Connor and told Trumbull to use him as he's ready to be their agent. Monroe laters watched a hot feed from the P.E.O.C. from the mastermind, who orders Trumbull to recall the Seventh Fleet and withdraw all 28,500 American troops from the DMZ. Afterwards, Monroe and the others followed tasks given by Trumbull.
At 10:23 pm, Monroe, Trumbull, and the other officials were informed that a Cerberus code has been entered, much to the dismay of Monroe and Trumbull. Later, Banning sends the Pentagon a picture of a tattoo on a dead terrorist's nape and they didn't recognize it. Trumbull tells Banning what the terrorists want and also reluctantly informs a Cerberus code has been entered. Although, Clegg insists Cerberus is classified, Banning persuades them in a tense manner. Trumbull informs Cerberus is a highly classified military protocol to access the self-destruct feature in ICBM missiles in the event of an inadvertent nuclear launch. The codes are given to the President, Secretary of Defense and the Chairman of Joint Chiefs of Staff. Banning suggests to change the codes. Monroe replied they can't because Cerberus was designed as a self-contained total isolation system and the only way to change the code is physically on the computer located in the bunker. Banning suspected this was the reason they wanted the President's son which astounded Monroe and the others. Trumbull ordered Mike to find Connor and evacuate him.
Minutes after 11:56 pm, Banning finally found Connor behind the walls of the Lincoln Bedroom. He told the Pentagon he found Sparkplug (Connor's code name) much to the relief of Monroe and the others. Banning managed to extract Connor and evade the terrorist's gunfire. Later Banning and Connor made their way to a ventilation shaft and told the Pentagon to have "the green party waiting". Two Army soldiers extracted Connor after he climbed the shaft. They manage to extract Connor undetected much to the immediate relief of Monroe, Jacobs and Trumbull. A pleased Trumbull then told Banning to try to get the President out now.
Discovering the Mastermind
After Trumbull returned from his press conference, Banning told Monroe the others the terrorist is Kang Yeonsak. Monroe examined the CIA database about Kang. He told everyone that Kang was brought along the DMZ as a child after his father was executed from crimes against the North Korean state and that Kang's mother was killed by an American landmine while crossing the border. Since then, Kang masterminded the 2004 bombing of the British Embassy in Seoul and funneled Pyongyang uranium enrichment technology from Pakistan. Monroe also stated that he was never photographed or identified by any Western intelligence agency. Monroe then blurted that no one even thought of looking for him inside the South Korean government.
Behind the Scenes