Hard to say for sure but looks like the bullet is traveling upwards. If and this is a big if, it is then not a problem if it fly's true. Bullet may of exited the rear of the skull/neck or that puff maybe the bullet hitting the skin but not penetrating out.

The light on the camera lens makes it hard to see clearly exactly what was what. On the surface of it I agree that the animals behind could have been hit so not a good way of doing things. Would have preferred a good soft nose/expanding bullet or Hydro to the heart, defiantly not a conventional solid unless it has a decent sized metplat.