I was in ATC at the North West Airfield, crouched in a corner where there is absolutely no visibility. I never heard a crack or shot, and was just instantly dead with a combat helmet and plate carrier.
My friend who was two floors behind me was camping the stairs, a person came in and threw a grenade below him and it exploded sending damage up the floor but he was fine. The enemy ran around a bit, paused, then without ever hearing a shot or sound my friend was instantly dead, same scenario - NO visibility from the outside. This was obviously a cheater. It happened around 4:30 EST on LA 7318. I really hope you all do something about this as it's ruined my will to play the game. It's hard enough.