Wow, I knew I was making a mess trying to explain what I understand in the song, let's see if I can state it clearer, but in fact I find it difficult 'cause these lines involve different clues, which I find related but not equal.
To start with, "we" from "We're falling from the sky" is the human race, us.
I think Bono is using two different images inspired on the Bible to tell us that we (the human race) are blinded by evil or, alternatively, that goodness in this world is being eclipsed by evil, so, consequently, "we are falling from the sky", a very apocalyptic sentence, which I translate to normal language as "we're being expelled from God's presence".
The great news is that in this song Bono is not speaking for himself, it is The Fly speaking, The Fly is a pub philosopher, a bar fly (do you use this expression in US?) who tries to make himself important by stating common knowledge as if it had a different relevance, most of the time speaking nonsense, that's the irony that impregnates most of Achtung, Baby and that's why many people thought U2 had lost their faith when they listened to it and when they saw burning crosses on stage at ZOOTV.
The Fly has also a lot to do with surrealism and we all know how much Bono likes surreal images (dreams of Dali with a supermarket cart, Lypton Village, etc.), in U2 by U2 he tells about having met such a guy in a popular club in Madrid, he started imitating him just to relax a bit in the Hansa sessions, but he ended up not only with a song, but with a complete character.
Well, I can't think of any other thing to make it clearer now, I hope you understand what I mean. I feel I must apologise, I can never give a short, direct answer, that's my bit of Celtic blood, I guess.