Comment by southernplaces7

>Imagine if it was intelligent and played witness to the giant cataclysm.

They'd have had to be watching from one very high orbit, and even then I wouldn't bet favorably on their chances considering the sheer gargantuan volume of debris Theia tossed into the space above earth.

Anywhere terrestrial and they'd be dead far too quickly to watch much of anything. I've seen some fairly detailed models on the presumed effects of this collision and it would have rapidly super-heated the whole Earth's atmosphere while vaporizing or melting the crust of the entire world down to a depth of at least several hundred meters. Good luck finding a bunker that can handle that.