Mod DB offers of beta version 1.0.5 of Traitor Mode for the Human Error co-op modification for Half-Life 2. Here's the reality TV-style concept: "The first version Beta 1.0.5 has two traitor mode maps. You play as the four metrocop characters from Human Error EP1. In the beginning of each round one of the players is selected as the Traitor, while other [sic] do not know who he is." Thanks Ant.