Complex sentence: He then pushes the unwilling Sophia into a mystical cage as a means of sending her to the Aetherium as an ambassador, and Indy sees no other way but to kill him to reclaim all parts and rescue her.
Split into simpler sentences: He then pushes the unwilling Sophia into a mystical cage as a means of sending her to the Aetherium as an ambassador. Indiana sees no other way but to kill him to reclaim all parts and rescue her.