How to avoid hurting hands when China ancient weapon projectiles fire projectiles?

Take a closer look at the bow of the slingshot. In fact, the hand-held part in the middle is tilted to the side of the hand holding the bow, so it won't hit the hand. However, it is still very dangerous to launch spherical projectiles with this slingshot. It is necessary to aim the maximum diameter section of spherical projectiles at the bowstring very accurately, otherwise it will not shoot straight ahead if there is a slight deviation, but it will fly around to the left or right, and it will be placed in the absolute center of the bowstring accurately, otherwise it will fly up or down. This shows how great the ancient slingshot master is!