I agree, we want to situate the arrow so that if it does break on release, that it does not go into the bow hand. The front portion of the broken arrow falls away since there is nothing pushing it forward. Tthe rear portion of our hypothetical broken arrow is still being propelled by the string towards the bow hand. This broken arrow, will break along the grain, diagonally, from the grain flame on the top, following that growth ring, to the grain flame on the bottom. This diagonal line will act as a kinda ramp, and will dictate the direction the back half of the arrow will follow, and we want this ramp to urge the back half arrow portion to travel up and over the bow hand, not down into it. Thus, we want to orientate our grain flames pointing towards the target on the top half of the arrow so that, if it does break, the broken grain line will be, from arrow top to bottom, going from further away to closer to the shooter. A picture is worth a thousand words, and I don't have one. I hope you are able to form a mental one.