The Chinese literally reads:
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If the earth dies, humanity will not continue to exist.
If one person dies, the earth will continue spinning as it is now.
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However, I seriously doubt that this is a mistranslation! (It doesn't fit the movie's story...)
Yes, ihminen, could mean one person or mankind, humanity. .. "If one person dies" would be "Jos yksi ihminen kuolee.." maapallo jatkaa pyörimistään niin kun se nyt tekee.