The sound from the helicopter's motor forced the mercenaries to raise their heads to check what was going on. They were shocked to learn that their targets' backup had arrived, as they weren't expecting the backup to arrive so soon.
For a little while, they were all caught up by the shock, and it slowed their reaction times down a little. And because of this, a few shots from the top of the hill were able to easily find their targets. The mercenaries who had been surprised by the sudden arrival of backup were hit, and their lifeless bodies tumbled down the hill.
More shots were fired after that from two other points in quick succession, and those were enough to confuse the mercenaries.
One of the mercenaries' snipers immediately touched his earpiece and contacted Big A. "Boss! We have to retreat right away. The lady is a better sniper than we thought. Their backup has arrived too. We have to go now or else it will be too late."