You need to take the knife when starting the game. When u kill enemies with knife by striking, they will die after 1 or 2 strikes. At that moment, they will die and give you score. On the part of taking damage, currently if you stay in line of sight of enemy, and if the enemy can see your hands then he will shoot bullets at you. Those will give you damage if the bullets enter your hand. VR has no body so your hands play an important part in gameplay mechanics.