John saw a glorious woman (the church) highly vulnerable due to her being in labour. Over yonder John saw a second sign, a hideous dragon of great strength (the devil). Now John sees these two entities merging into one picture, with the dragon coming to stand in front of the labouring woman. The Greek uses a form of the word “stood” to make clear that the dragon is parked before the woman; he’s not going to move. Meanwhile, labour being what it is, the woman has no choice but to deliver her child in the presence of the dragon. The picture is terrifying even for the reader!
4 His tail swept down a third of the stars of heaven and cast them to the earth. And the dragon stood before the woman who was about to give birth, so that when she bore her child he might devour it.