At the end of the game, Gordon is captured by Dr Breen, who already holds Alex and Eli Vance. Judith Mossman, who had earlier betrayed Dr Vance, is with Breen. Dr Breen takes this opportunity to brag about the situation, revealing that Gordon's services are 'open to the highest bidder'. As he threatens the Vance family, however, Mossman turns on Breen and frees the pair, along with Gordon. Alex and Gordon chase after Breen while Eli and Judith escape. At one point, when they catch up to him, he is apparently bargaining to be removed from Earth via a host body. He agrees to do this, and flees to a teleportation chamber. This, due to the Combine's teleportation technology being far clunkier by comparison to Earth or 'Xen', is a massive chamber powered by a dark fusion reactor, which Gordon manages to destroy. Does Breen escape? We don't know. The G-Man pulls Gordon out of reality and shoves him back in stasis. Presumably Episode II will tell...