Clay shoots Mary Lou off-camera. He is standing at the time and she is kneeling upright.
However, later it can be seen that her wound is to the left of her stomach. Instead of taking the obvious head shot which would have killed her instantly, Clay would have had to bend down and shoot her in the area of her kidneys, something that could technically be survived.
There is no reason for him to shoot her in this way. However, it is obvious that this is done purely to set up the 'angel's wings in blood' shot later when she crawls over to Josiah and eventually dies.
However, later it can be seen that her wound is to the left of her stomach. Instead of taking the obvious head shot which would have killed her instantly, Clay would have had to bend down and shoot her in the area of her kidneys, something that could technically be survived.
There is no reason for him to shoot her in this way. However, it is obvious that this is done purely to set up the 'angel's wings in blood' shot later when she crawls over to Josiah and eventually dies.