Complex sentence: The UN-Forces, however, see the Birdman as an uncontrollable liablility and launch several Nuclear Missiles at the birdman, Sara sacrifices herself to save Shin and the rest of the Mayan island which would have been destroyed by the nuclear fallout.
Split into simpler sentences: The UN-Forces, however, see the Birdman as an uncontrollable liablility and launch several Nuclear Missiles at the birdman. Sara then sacrifices herself to save Shin and the rest of the Mayan island which would have been destroyed by the nuclear fallout.