Derka Mode (Also known as "Infidel" Mode) opposed to it's racial meaning, When you enter a game lobby and fly in a helicopter, but you are shot by bullets rather than rockets, even though Rockets are available, so whoever is shooting you is shooting you in Derka Mode. The name "infidel" comes into play if the shooter(s) believe that they cannot hit the enemy with a standard non-guided Rocket mainly because it can't lock on, but that is a proven lie. The most common places for this is in Battlefield and Halo.