Why did David cry while destroying the engineers?
While having a discussion about why David cried in that scene I had mentioned it was just like when Lawrence (Lawrence of Arabia) had to shoot Gasim for what he had done. He had to execute his friend to preserve peace and eliminate any possible revenge that could happen if Bedouin had carried it out themselves.
David and Lawrence both understood that to create a new world there needed to be sacrifices made, the old world of cruelty and indifference destroyed – @muthur9000
That was a key moment when Lawrence had to shoot Gasim… and admitted afterwards that he ‘enjoyed’ it, which horrified him. It revealed so much about him, below the pragmatic surface.
I found this quote that expresses some of the common themes between that execution and what David does:
“In the film, Lawrence’s godlike power to give Gasim life is soon mirrored by the godlike power to deprive it.” Lawrence’s description of his experience, and the almost-botched, bloody execution, implies the trauma that could be occurring in David. But even though it’s traumatic, it’s necessary. To clear the way to use this world, and be safe in it, and indirectly punish the Engineers for creating humans in the first place and being inferior gods who tried to destroy David himself. – Executed today 1917: Gasim, by Lawrence of Arabia