You shouldn't kill your team in a game.
Harold was online playing a first person shooter with his friends.
Harold wants to kill some of the other players.
Harold sneaks around and kills all of the members of the opposing team.
Harold goes around and kills all the other players on his team.
Harold's team is happy that he did so much to help him win the game.
Harold's team is upset and kicks him off of the server they are playing on.