Allow me to explain citing the Divine Code by Rabbi Weiner, Second Edition, page 299. The prohibition against eating flesh taken from a living animal applies only to domesticated mammals, wild mammals and birds. God also did not grant permission to eat human flesh, whether or not it would be removed while the person was alive. These four categories of living beings are represented by the four faces of the hayot angels of the divine chariot: the faces of the ox, lion, eagle and human. Since these angels are elevated to the highest levels of the heavens, we can speculate that God gives an extra honor to their reflections in the physical world through the Torah's universal restrictions on eiver min ha'hai and cannibalism.