Board Thread:Show-Related Questions and Answers/@comment-26116863-20151117024202/@comment-6175354-20151117163109

Eskaver wrote: The Dark One can die, only by Excalibur. Excalibur cuts immortal ties. I don't think you guys were paying attention.

The plan would not work, because Excalibur mortally wounded Hook. Once the immortal ties are cut, he will probably still die. Emma is just too desperate, to realize that.