When the ai health reaches 0 you should make a branch with your Boolean (dead) and drag false into your death code and set dead to true at the end of all of that. That way he can only die once. Another way to do it is to only apply damage if his health above 0. You will have to get a > node from your health float to see if health is greater than 0. If yes then set health to health - damage with a clamp at the end. Clamp it from 0 to a high number. The add a < to the resulting float value to see if health is below 0 after the damage is dealt. If yes then do your stuff. You can also just deactivate the skeletal mesh, that way you would only have to add one node. Just drag out the mesh and type deactivate