Board Thread:Spoilers!/@comment-3010035-20150701044944/@comment-24674051-20150702143003

My guess is that, just like Rumple was at times in control and good still (occasionally) make good choices, so Emma still has some control over her actions, and while she could she deliberately dropped the dagger for the others to find. I'm hoping that the answer to this question is explained in Dark Swan.

As for why Emma (possibly) jumped realms, first we don't know that for certain, though i imagine that question will be answered in the first 5 minutes (and possibly revealed in a sneak peek at SDCC, since rumor has it that Emma's opening scene was actually filmed when they filmed the Finale). But if it is true, it could be because, probably unlike earlier dark ones, Emma was a powerful Sorceress to begin with, and the darkness is just going to augment her power. I thnnk Emma as the Dark One would make Rumple at his worst look like a tame kitten by comparison.