Reflex Mode

Reflex Mode is a new feature that will appear in the upcoming games Metal Gear Solid V: Ground Zeroes and Metal Gear Solid V: The Phantom Pain. It allows players a chance to stop a guard from causing an alert and works on all enemy soldiers.

Hideo Kojima's reason for including this is because the enemies in the two MGSV games can go anyway in the area and are unpredictable. There is an option to turn this off and Kojima confirmed that players will be encouraged to not use Reflex Mode and will get rewarded if they do not use Reflex Mode.