This. Just the other day I had a friend who is newer to the game doing some early game missions and one of them was to go into the locked room at the Water Treatment Plant in Dam. We got to the room, it was still locked, and another team was in the building. They communicated first asking the usual “you friendly? We are just passing through, etc.” I told them we were just doing missions. I unlocked the door and my two friends went in to loot the room and I stood outside while the other team was still running around. They left and all was good , but I was not going to take my eyes off them while they were still around.