Hope and prayer are not ethical questions or actions in hunting. Patience and waiting for the correct shot is the only thing that should enter your mind. Letting a trophy walk away because it never gave the right shot is the measure of a true hunter. When using smaller calibers for deer it is vital to get the bullet into the heart or lungs. The problem with a frontal shot with say a 243 is most likely there will be no exit hole and nothing much from the entrance hole for blood tracking. Be patient most times a few more steps and the deer will present a better shot. I'm not an advocate of neck shots for the majority of hunters as the margin for error is huge.