The Apocalypse Has Not yet Come, How to Activate the System?

[The host comes to the lair of a strange creature] But in front of Qin Sheng was clearly the back street of the school. Warn! Warn! Warn! A group of level four corpses appears ahead! The system is hot! But in front of Qin Sheng were a group of clear and stupid college students. [Three corpses appear in front of the host. They seem to have resources on them that can be looted. Qin Sheng faced his roommate, but the system issued this reminder. Peaceful campus life, but the apocalyptic system is activated in advance? The former classmates will turn into zombies and turn into dead bodies in two years. Qin Sheng relied on the system that was activated in advance to collect supplies before the end of the world and changed the fate of his classmates who had turned into zombies in the end! Two years later, when the end of the world truly came, Qin Sheng sighed: I am invincible!