Thinking out loud, dispensationalism

Pre-trib rapture of the church (2nd Coming)

Start of the millennium (3rd Coming)

given the apostasy at the end of the millennium–per the dispie system–is Jesus present in Jerusalem during the apostasy? (further, how can there be sin and death in the eschatological presence of Christ?)   If so, big problems entail.  If not, does he come again to throw Satan into the fire (this posits the fourth return of Christ)?