^ Did you not see "Kansas" or catch the blatant flashbacks to that episode in tonight's episode? The good guys apprehended her before she could cast her portal spell and put her in jail, but Rumple showed up, turned her into glass with the real dagger (after having given Belle the fake one), and then shattered her body, but her essence survived and traveled across town to activate the time portal seal that sucked Emma and Hook into the past (as seen in "Snow Drifts" and "There's No Place Like Home").
I do recall the scene where Rumple stabbed Zelena and turned her into a statue. So that must have occurred after Regina defeated her in a face-off at the barn.