But what if...

Like this version or not... hypothetically, if Alexander, after having travelled 4 years into the past to save Emma, had taken her not to Bleaker St., but back to his home, explaining a bit about his invention... and taken her 'back to the future' (sorry) 4 years to just moments after he'd left... do ya suppose she would still have been killed in some way, then?
There's all sorts of theories regarding time-travel, whether it can even happen, or that there are built-in safeties to prevent paradoxical conundrums (grandfather paradox, etc.).
That scenario, to me, seems like his reality would seem to balance... except for her disappearance, four years prior, would create alternate time-lines, which would intersect poorly, once they reappeared four years later... together.
Of course, if they both just relocated in a more distant future (or past), that may not be the case.
But, would Emma's death still be a debt that must be paid... or not?
I invite conersations/theories/debates.