I read an interesting theory that the headroom was actually like a graveyard of sorts, maybe of dead engineers. If you look at the way the Black Ooze acts when David tips the ampule upside down, it looks just like when the Engineer plunges into the water after drinking the Black Ooze.
Pithos  is the Greek name of a large storage container. Pithoi had been used for bulk storage, like fluids and grains. Discarded pithoi made a convenient coffin and was used by Ancient Iberian cultures from 1300-1500BC
In warfare, the pithos full of flammable olive oil was a liability to the defence of a palace. An enemy had only to knock over a pithos full of oil and touch a torch to it to produce a major conflagration.
- Henry George Liddell; Robert Scott (1940). “πἰθος”. A Greek-English Lexicon. Revised and augmented throughout by Sir Henry Stuart Jones with the assistance of Roderick McKenzie. Oxford: Clarendon Press.