Is Black goo more powerful than we thought??

Good observation....I have thought about this before but blew it off as an inconsistency... But thinking about it now after seeing eggs in covenant it is a possibility you could be right...this is what I love about this universe, gets ur mind wandering

The eggs in the new film look quite a bit different than the eggs in the original Alien. I'm wondering if they are mutated urns 

I think its inconsistency, but as for the engineers being chased by a xeno on lv223, no, i think they had an accident and they all went crazy and blew up, literally.

Guys, I need to point out David sprayed his urn down and re-froze it with nitrogen before bagging it and taking it back to the ship. 

I can't find any pictures showing him re-freezing it

It is never outright explained in the movie but the urns are like grenades, they need to be primed first. The Urn that David snatched was a dud that didn't fire when he and the humans entered the ampule room. This is evidenced by the many urns see later on aboard the Juggernaut, which are set within a similar environment to the ampule room but did not react to the same atmospheric conditions

Inside the urns, the black goo is stored within those vials, one of which David examined. When the Urns are primed, the black goo is released, mixes with the surrounding material (the slime) and leaks from the urns - a good analogy would be the bomb found in the school in Die Hard with a Vengeance. 

Rick, here you are:

I believe the urns were reacting to the changing environment in slightly different speeds in relation to releasing the black goo. And that is why David 8 was able to arrest this activation of the urn with an intact lid with freezing it until he could study it.

I believe the top of the urn dissolved upon activation and the movement seen it the churning or agitating of the black goo out of its glass housing inside the urn to enable distribution outside the urn.

Many industrial processes are similar in the agitation of the ingredients to activate a complex process with a reactive substance.  

Indeed totally going to agree that David Froze the Urn and then it went right into the Freezer on Prometheus.

I will bring up a Potential Plot Hole in Alien Covenant however..

Ridley Scott also conducted a Interview before in-front of these Urns.

We can maybe consider the Urns are Activated by the Respiratory System of Humanoids or Life in General, which would explain why the Engineers wore those Suits as they could breath outside on the LV-223 Surface.

This would explain David could handle the Urns without them being triggered.

This is the only explanation for how he could store the Urns in the Catacombs without them going off, unless these are just the Empty Canisters after the contents has been used.

Because surely if not, then at very least any Human Explorers get near these Urns then surely they would get triggered?

@BigDave

The freezing thing makes sense, it just seems odd for the substance in the green containers within the urns to bubble on top of the urns before they are taken out of the green containers and urns....i mean if it is going to bubble on top of the urns when the atmosphere/environment is disrupted why have the green containers within in the first place, right?>?>

I hope i asked that properly, but it doesnt make sense. Freezing them to keep them from going off does explain alot but not the fact that it is housed inside the green vases and still goes off....maybe im over thinking it but just seems odd 

Also i feel you are onto something, the urns seen in the workshop behind Ridley are clearly not in a contained facility so why are they not reacting, it might be an inconsistency. That is one thing i wish they would flesh out, how exactly the urns work, they can leave the goo being volatile with crazy different outcomes if they want but i would like the urn system explained so we know what to look for in the movies and the rules that they need to follow to not have this stuff go berserk.

@BigDave

I think its a stretch from a story telling aspect to have the urns go active when humans are nearby, it just seems a little silly , so i hope they do not go that route...i feel that the determining criteria for active or dormant lies with the temperature/atmosphere/ just my thoughts

@G&DL I totally agree with you. I didn't like the whole "Black Goo" mechanism and how it all didn't work well. The sequence you mentioned is the one that really had it all fall apart. Liquid Nitrogen might freeze it for a minute, IF it is submerged into a vat of it, but it would rapidly come back to room temp, PLUS David, after he stole the ampule(s), was around all the humans in the transports, so it would've EASILY "reactivated" or whatever the hell it is.

Count me out on the whole Black goo thing. It's just too "X-Files". I never liked it, and it really doesn't work...yet.

@Starlogger

I agree that little spray gun of Liquid Nitrogen wouldnt keep it cool long enough and then if it was like the rest you would have all of the bubbling of goo on top, but i agree it needs fleshed out....the green tubes inside the urn should keep it from bubbling out otherwise why have them inside the urns in the first place???

While i really love the idea of mutation and the story telling it opens up they need to clean up the rules about the goo and the urns...right now there are a lot of inconsistencies...i may regret saying this but i am fine with whatever way they go with it as long as its consistent and not "hokey"

The only way i can think is that Temperature has a massive effect too as i am sure Ford Mentions something about the Temperature being Minus something but dont qoute me on that.

I know Holloway mentions about outside their is Lethal Co2 but inside its clean and breathable.  so i can only assume Temperature and Co2 or something else to do with what we breath out is what is effecting the Urns.

Here is the Urns and first image is the Concept and Last the Weyland File Fox Released, the Center Two are from the Movie

I think its safe to assume that the Glass Vials are separated and surrounded by some other Chemicals which include the Slime and we have to assume when conditions arise to activate the Urns these TWO components mix and cause a reaction and that this can somehow effect the Top of the Urns that must be either sealed with a different Material or the inside of the Urns a Reaction happens that effects the Top pointed part of the Ampoules to React with the Lid of the Urns.

@BigDave

She said it was -12 degrees in the movie right after they take their helmets off. I think what you stated in your last paragraph may be on to something, like a chemical reaction after they are "awoken" by environmental changes and the slime and the contents combine to some effect

I figured the ampule room was airtight. So, when David opens the sealed door (which has been closed for 2000 years) air comes into the room and starts the reaction. This is also why the engineer head is preserved (but disintegrades later on)?