Walking in the Doomsday

After reading a few chapters, I realized that the reason why the protagonist has the ability to save people but is filming a video as if nothing happened is because the protagonist wants to save all mankind, not you. Whether you can survive until the day when the protagonist is interested in saving all mankind depends on your own life. I have never figured out why the author asked the protagonist to take a video record? In the sudden apocalypse, wouldn't it be more efficient for the surviving scientists to study this? Isn't this the same as the warrior in the game who uses all his strength to attack the BOSS with fireballs that don't break defenses, and then looks down on the output of other little mages who barely break defenses? I don't know where the fun is. He can neither show his holiness in front of others, nor is he the mastermind behind the scenes. It feels like being a bystander, mainly relying on self-pleasure.