According to the in game prophecy in the Following, "when the world is ravaged by a plague, when darkness devours the earth, when men are as beasts to one another, when humanity shall be struck by corruption of both flesh and soul then shall be revealed one man who, through an act of ultimate sacrifice, shall accept the Mercy of the Light. And the God of the Sun shall be revealed through him and through him will he speak, and his voice shall be the light and the healing. And he shall pass through the gates of death so that he may bring new life." We can deduce the proper ending for the game.

The game revolves around a religious group called the children of the sun who looks up to a central figure they call the mother. Mother decides which path her children should go. This title is passed on from Mother to Daughter in continual succession. However, one prophecy reveals that a man who's supposed to be a vessel for the God of the Sun shall take over and that "Mother" shall bring this prophecy about.

This took me at least an hour to figure out and at first glance it seems that the first option is the canoncal ending. It's your typical sacrifice thousands in order to save million ending which the ministry and the GRE has been trying to accomplish (which is the big red flag). It also seemed to make sense considering that the "god of the sun" is supposed to eradicate the plague: the interpretation being "god of the sun" is equals to nuke. However, upon closer inspection this doesn't make sense if you reach the finale having completed all the side quests . Why doesn't it make sense? Because the Quarantine zone blockade is no longer there

Tolga and Fatin, the two stupid geniuses of the story line looked like they died when they built a rocket train to blast through the blockade when they didnt response to Crane's radio transmission. However, Upon accessing the door leading to "mother" they let Crane know that they're still alive. How is this relevant you ask?

Harran has been quarantined all this time to prevent the virus from getting out. This all changed when those 2 idiots rammed their way through out of Harran. This may seem like a comedic twist but this is actually a matter of details that might lead us to what might happen in Dying Light 2.

What is my point? Nuking Harran is supposed to eradicate the virus to prevent it from spreading outside Harran. But as you see, Tolga and Fatin destroyed the blockade which is most likely a volatile hive. The blockade not only prevented the people of Harran from getting out but it also prevented volatiles and the infected from venturing outside Harran.

That being said, Nuking Harran will no longer eradicate the plague. It will only be a pointless mass murder.

But the real question here is, How is option 2 a fulfillment of the prophecy? According to Mother, being a sentient volatile filled her with love and compassion during the day (perhaps this the chemical's effect to the brain). the prophecy also said that Mother will bring about the God of the sun (crane imo). Upon choosing option 2, Mother forces Kyle to drink a whole vial but Kyle managed to spit out some. This act brought about the God of the sun which will transform Crane into a being of compassion and mercy in the day but a murderous night hunter during the night? This may seem like a contradiction but we should look at the prophecy a bit closer.

The prophecy mentions that the man of the prophecy will pass through the gates of death so that he may bring new life. Choosing option 2 will allow crane to live but will he continue to stay alive in Dying Light 2? Being a sentient volatile brings about many different options on what Crane might do. We do know that he retains his intellect during the day but the sun prevents him from going out therefore rendering any effort useless. Also, how would choosing option 2 eradicate "the poison that plagues the earth?"

In order to eradicate the virus, you need a cure. Small pox was eradicated when they developed a cure. Quarantine is only taken as an action to prevent an epidemic from happening. Therefore, the cure is the answer to eradicate the plague. So how will Crane pass through death and also bring new life? Its very possible that Crane will attempt to bring the vials during the day to Dr. Camden so he could study it (he's a sentient being during the day) and as a result of this attempt he will die of sunburn. This completes the prophecy of him passing through the gate of death so he may bring new life.

That being said, Dying Light 2 will not only involve harran but we're talking a global spread of the Harran Virus whether you choose option 1 or not. Choosing option 2 is the only way to save humanity from the Harran Virus.

If you have any questions, contact me and I'll try to modify this guide to answer your question.