Gordon reaches the administrator's office for the climactic confrontation with Wallace Breen and the leaders of the Resistance. Mossman eventually regrets that she helped Breen, and betrays him by releasing Freeman, Alyx, and Eli from the pods. Breen attempts to kill them by using the supercharged Gravity Gun and escapes with it. Alyx and Gordon finds him arguing with an Advisor and escapes before they are able to get to him, leaving the Gravity Gun on the floor. They open the windows and find the Dark Energy Reactor at the very top of the Citadel. Alyx lets Gordon down to the Reactor where Breen starts ascending and opens the Combine Overworld portal. Gordon destroys the reactor, causing it to fail and begin to go critical. The reactor explodes, apparently killing Breen and nearly taking Alyx and Gordon with it. As the reactor detonates, however, the G-Man freezes time and addresses Gordon. He is put back into stasis by the G-Man.
