I noticed something since witch queen and I have to say I busted up laughing watching what these NPCs do. I throw a grenade it doesn't matter what grenade as soon as the grenade hits the floor or whatever it hits the NPCs look around and start heading for the grenade as if saying here let me help you. It is so funny. One time I throw a grenade it looks for the grenade and tells their buddies hey it's over, omg it's great. Try it once and you'll see what I mean.