It never said they were made to be immortal, just that they were made in God's image. Their punishment was not mortality, it was suffering and hardship. You are making shit up that isn't there. In fact, the Bible heavily implies that they were mortal in Eden before the fall. God banished them from the garden because he feared they would eat of the fruit of eternal life, which would allow them to live forever Also, God had said that those who ate of the fruit of the knowledge of good and evil would die on the day they ate of it, not that they would die eventually, but that they would be dead by sunset if they consumed that fruit, it turned out to be a lie. The serpent told the truth, that eating of the fruit would make them bevone as God, knowing good from evil, who's is the exact wording of what had happened after Adam and Eve ate of the fruit of knowledge. Mortality was not one of God's curses on Adam and Eve, instead, it was that Adam would toil and fight for survival of himself and his family, Eve would suffer to bring life from her womb, and that the serpent would lose its limbs. The lands outside of Eden were different from the garden in that they had the four bringers of suffering and loss, war, famine, pestilence, and unnatural death. Natural death, it seems, was always a part of the plan, and God had feared that his creations would attain eternal life. Just as how he had feared that a tower which rose above the clouds would allow mankind to challenge him and threaten his dominion.