 The other side of that, out of line of sight, is that reverse slope. They didn't cover that. So if you're a gunman, you go on the reverse slope, you hide behind the cover of the roof, and you can barely pop up and you can take your shot. And it makes it very difficult for countersnipers to hit you, to spot you, that sort of thing. So the civilians behind the shooter saw the shooter and were trying to flag the teams to go ahead and deal with it.