How do I exit the darn loot screen?! I must be a moron because I can't seem to be able to do that. Escape takes me to the system/general stats/quest screen and I can't figure this out for the life of me. This is infuriating!

Press Tab.

Oh thank you sooo much!! Sorry for having to make a post to figure that out.

Ha, it took me some time to figure that out myself. It was frustrating to say the least!

That's also about as much as I've played so far, where I had to exit the first loot menu - hitting escape like a monkey.

It was a confusing moment for me as well, so you are certainly not alone.