We need to look at the Theme of Prometheus for Answers...
The movie was about these Beings who we was Genetically Related too... the Engineers on LV-223 and the Sacrificial Scene (include Elders too) are Genetically connected with Mankind...
The movie shows a seeding of DNA via a Mutagen Goo..... then also a attempt to destroy Mankind with another type o Goo.... which failed due to a Outbreak...
The other theme was about Creator, Creates and Creation then starts to behave or turn out in ways the Creator never intended or feared..... and so Creator attempts to Punish their wayward or failed creation..
We see hints that David is showing signs of functioning in ways not intended and to act for his own desires and not his creators..... Its hinted.. but more so in Ridleys comments that the Engineers may have done the same with their Creators. Or at least Hierarchy
Paradise Lost was a theme they was touching on... this is a theme that can still connect....
*We have God... who could be replaced by Gods (or the Top of the Hierarchy).
*We have Chosen Creations of the God/s who some Rebel against the rule and we have a War and the rebellious being Punished and Evicted from Paradise/Heaven
*Mankind is created, as a replacement and then Mankind is corrupted and then also Evicted and will Face numerous Punishments over the years for going against Gods Rule.
I think these themes are Loosely at Play.
This Disaster Scene would then be some kind of Punishment, its a case of is this Scene Punishment via...
*Gods/Hierarchy on the rebellious sub-creations.. be that rebellious Engineers.. or similar?
*As above but on some related Race who connect to Mankind and Engineers.. a earlier Ancestor of Mankind?
*Punishment against the Hierarchy/Gods... by their creations or rebellious Faction?
*Punishment to the Gods/Hierarchy new favored creation by those who were against the Gods/Hierarchy.
OR.....
Punishment brought by David... which without good reason, and not allowing David to find out some of the answers Shaw and the viewers wanted... to relay them to us.. via maybe David being able to interpret before or after this Disaster what the Agenda was... of those beings and Engineers.
A Flash Back from a more Ancient Event could serve as a Narrative to explain those Big Questions more than David just unleashing Hell on them.... unless there is a event prior to this that we would get some information on WHY.
I hope they dont go the Whole...
Mankind created David because they Could..
Engineers created David because they Could..
So David destroys Engineers and creates something to use on the Covenant Crew and Mankind... because he COULD..
That would be a COP-OUT