This is mentioned in both Matthew and Luke and neither one addresses the store in its entirety
It says two men will be in the field. One will be taken and the other left behind.
Meaning two secularists and unbelievers and skeptic Christians and agnostics will be in the world. One will learn to believe in God while the other will continue to be an atheist.
Two woman will be grinding with a hand mill. One will be taken and the other left.
Meaning two worshipers with false theology will humble themselves before God and seek Him and suffer for Him. One will learn correct theology over time while the other will continue to practice, believe and teach false theology.
Two people will be in bed together. One will be take and one left.
Meaning two people will have correct theology but misuse their knowledge of good and evil by condemning and judging others. One will learn to forgive and atone for the times they destroyed others. The other will continue to be vindictive and judgmental and hateful and exclusive and morally classist and stingy and bitter and resentful and ungracious.
So to become God’s elect
You must acknowledge God’s existence
You must acknowledge God’s justice
You must acknowledge God’s graciousness