In Prometheus when Fifield and Milburn are trapped in the pyramid because of the storm, they come across a pile of dead engineers. Holloway also states when they enter the Head Room that “It’s just another tomb.”

This scene shares some similarities to Dan O’Bannon’s original Alien Script, which can be found in the AVP Galaxy downloads section.

Broussard: I’d bet my share on it. There’s no doubt in my mind.

Melkonis: Poor Yorick (space jockey) must’ve thought it was pretty important, used his dying breath to scratch it on the panel. (They are talking about a triangle shape etched into the panel in front of the space jockey)

Faust: A warning?

Standard: An alert certainly.

Hunter: To who?

Standard: Whoever came along.

Roby: Whoever’s stupid enough to land.

Broussard: A marker for buried instrumentation?

Hunter: Tombstone

Standard looks at him, at the pyramid.

Standard: Hell of a big tomb.

Hunter: A tomb or a mass grave.

Broussard: or maybe they’re alive in there. Or hibernating. Or in suspended animation. Waiting for somebody to come along and rescue them.

It’s just another part of the original script being used for Ridley’s prequel series, I think it’s nice to have Dan O’Bannon’s vision brought to life.

This symbolism is also present in Prometheus and in Alien: Covenant

The Raft of Medusa in Prometheus

The Engineer’s Demise and The Punishment of Thieves (Coming Soon)