If an aggressive animal or monster was heading towards your child's direction, would you get in between? This means accepting you're literally dead meat. 100% chance your child is saved but 80-90% chance you'll die. If you survive you're going to suffer serious injuries.
Meanwhile your child is safe (as the animal or monster got distracted by you, going after you instead) and ran to safety, you're either badly injured, mauled to death or devoured. If you're a grandparent, same... would you do that for your grandchild?