Sheila may have moved/tilted her head herself before she died. Her mouth would have been full of blood to have made her bawk,leaving the running blood to find its own level. This part of the reflex ( choking ) would have just about been functioning before brain death. Many people "cough up" before dying and Sheila would have had an overflow of blood for it to have run down either side of her face and she'd have been in a dorsal position for that to have happened and not necessarily moved.