Those who are false believers will be brought to light. And those who have not yet chosen Christ will have that option. Think about this, if there is a pre trib Rapture, why have the Tribulation at all? A pre trib rapture IMPLIES all of the Righteous are gone. The wicked already have Hell, why a Tribulation too? There will be some sheep hidden in with the goats. The Tribulation will bring them out. Why then would the Good Shepherd leave sheep without a shepherd? We must all be prepared to go through the Tribulation. Steel gets stronger when it goes through the fire. Besides, we have work to do. Trying to save people in a world that is doomed. It is like Josiah. He read the scroll they found in the Temple and asked God about it. God told him Israel was doomed. They had sinned too much. But Josiah still did his best to make things right, even knowing it was too late. We have to find the last remaining Chosen before the Second Coming.
What many do not understand in all of this Pre, Mid, and Post-Trib argumentation is that the "Tribulation" was defined by Jesus as applying to the *entire age.* Yes he did!
In Luke 21 Jesus defined the Great Tribulation as the greatest punishment the Jewish People will ever have to go through, lasting for the entire NT era. Because they rejected their Messiah, their people, as a whole, have had to go through wandering without a homeland, up until recently. They are still in trouble!
So what people are so concerned about, namely the "Tribulation," has actually been going on throughout the NT period. It began in 70 AD with the Roman destruction of the Jewish Temple and Jerusalem.
At that time, Jewish believers in Jesus had to go through it too--not because God's Wrath was being poured out on them, but only because as Jews they had to go through what their unbelieving brethren had brought upon the people as a whole.
Jewish believers suffered the abuses of their unbelieving brethren, which is precisely why God sent the nation into this Tribulation, to judge the wickedness of the people generally at that time. And Jewish believers, once scattered abroad like the rest of their brethren also suffered abuses from the pagan countries into which they went.
This is the state of Christianity throughout the present age. We experience blessings from God for our obedience. But we also experience Tribulation from the unbelieving population around us.
So a lot of the hype about a future Tribulation is just Futurism on steroids. Lest you think I'm not a Futurist I want to say that I am a Futurist--just not believing that the coming Antichristian reign of Terror is particularly worse than anything in history thus far.
The portrait of the rule of Antichrist was given to the historic Church to warn the Church in all ages, and in all countries. It is our common experience, as it will be at the end of the age.
The Reign of Antichrist is coming. But there have already been many Antichristian reigns. This is just one last one--not greater than the others, but only the last one.
The "Tribulation" was called the "greatest in history" only because it is the longest Jewish punishment in history--not because it is particularly more severe in the short term.
Satan is not omnipresent--he only seems such because he apparently has hordes of demonic followers. Neither will the Antichrist be omnipresent, encompassing the entire earth with his rule. He will rule primarily in Europe over 10 nations.
But his influence will be global because sin and rebellion will be global in this last phase in history. It will be a post-Christian world. The demons, having been cast out, will bring back with them 7 more. We need to stay prayed up, and we will prevail, with God beside us.