In the scenario I proposed, Zelena wouldn’t be out to kill Emma. If Neal escaped and went to find Emma, Zelena would likely follow and try to kill Neal to prevent him from kissing Emma. Promises to and retribution from Rumple be damned if things escalate to Neal escaping. Zelena still can’t kill Emma, because that breaks the Curse, but eliminating Neal once and for all means that TLK can’t break the Curse any more, and the only remaining way for the Curse to break is with Emma’s death, and no one’s gonna kill Emma, so Zelena resumes complete control as long as she can off Neal. I could see it if Zelena is going after Neal and Hook intervenes to protect him, and sacrifices himself in the process.
PS. Didn’t Daniel say he’d figured out a fix for the spoiler quoting? Because we really sorta need that fixed.