Mark 13:20 “And unless the Lord had shortened those days, no flesh would be saved; but for the elect’s sake, whom He chose, He shortened the days.” Doesn’t this tell us that at least some of the Elect survive the Tribulation, and go into the Millennial Kingdom?
It could, but the elect includes many more than the 144,000. It can refer to any believer on earth at the time. Also, the Greek word for “elect” does not appear in Rev. 7 in reference to the 144,000.