Here my thoughts, DecemRationis:
Some have said that the 6th seal, the 6th trumpet, and the 6th vial concern the time of Antichrist. With the 7th seal/trumpet/vial the "kingdom of this world is become our Lord's and his Christ's". E.g.:
[12] And I saw, when he had opened the sixth seal, and behold there was a great earthquake, and the sun became black as sackcloth of hair: and the whole moon became as blood: [13] And the stars from heaven fell upon the earth, as the fig tree casteth its green figs when it is shaken by a great wind: [14] And the heaven departed as a book folded up: and every mountain, and the islands were moved out of their places
Sun/moon/stars/heaven like in e.g. Mt 24:29. During the time of Antichrist (first part of the consummation) Sun and moon (Christ and Church) "in eclipse", the fig tree (Church) loses her fruits (apostates) = stars fall from heaven (apostates). Heaven (Church) is folded up = locked down (no shepherds). Mountains and islands (=mountains of the sea) moved = all which was firm, law and order and Church teaching, put upside down.
After the sixth seal and before the seventh, in Rev 7, before the second advent the servants are marked.
Ez 9:4 "mark Thau upon the foreheads of the men that sigh, and mourn for all the abominations that are committed in the midst midst of Jerusalem"
Mark those who didn't fall for Antichist, mourn the abominations committed during the time of Antichrist in the Church (= Jerusalem).