What is the trope in the film "Life of Pi"?

"The Life of Pi" metaphor: There are no animals on the lifeboat at all, the crippled zebra is a Chinese sailor, the orangutan floating on the banana is Pi's mother, the tiger Richard Parker is Pi, and the hyena is Father Pai is not a chef. The mouse eaten by the tiger was Pi's girlfriend Anandi. The teeth are Anandi's teeth. The story told in the film is actually this: an immigrant family is dispatched, and the young man and woman are reluctant to leave. The dispatch hides their girlfriend in a lifeboat. After the freighter crashed, Pai and his family boarded the lifeboat where his girlfriend was hiding to escape. The Chinese sailor followed and broke his leg in a hurry. After drifting in the sea for a long time, the first to starve to death was the Chinese sailor who was not his family member. He was the weakest, and the only food on the lifeboat was given to his family. Then the sensible father cut off the flesh of the Chinese sailors and fished them. Pai and his mother are devout believers. They rejected his father's approach and refused to eat without knowing the danger. Once, after a huge conflict with his father, his mother was angry. Suicide, Pai accidentally killed his father in excitement, but the father who loved his son gave up resistance in the grief of losing his beloved wife.

The ensuing drifting and hunger kept attacking, and the dying Pai had no choice but to kill his weak girlfriend and use her girlfriend's meat to fish like his father until he was finally rescued