Shen Yue decided to destroy those modern weapons.
He knew that some overly advanced things would not only fail to advance human development but instead become instruments that pierce through the moral baseline of humanity.
People who possessed lethal weapons never considered the entirety of humanity; that was the consensus of his era.
Shen Yue specifically pointed to the grenades and reminded them, "These round objects are called grenades, and they must not be hit, or else a very powerful explosion will occur."
Yang Yao was slightly stunned, thinking to himself that if these items could exert great power in the enemy's hands, wouldn't we be able to use them in the same way? But out of absolute trust and admiration for Shen Yue, knowing Shen Yue must have his reasons, Yang Yao picked up those guns and ammunition and threw them into the well.