Amy asks what he'll become, and River's all nervous like, "Oh, the Doctor's the Doctor," and Amy gets sassy about it, and River turns to the Doctor: "Yes, we are. Talking about you." He prissily pretends to be busy, but they seem to be getting his goat in a very Sarah Jane/Rose kind of way, and she tells him to turn his instrument back right side up. It's nice, in its way. Amy accuses River of being his wife, and through her protestations -- "Do you really think it could be anything that simple?" -- Amy's like, "Duh, yes." And then River likes her back. Which is to say, River for the tenth time in as many minutes tells Amy how special and amazing she is.
They stare up at the catacombs, and it's totally awesome looking. Meanwhile, some expendable soldiers talk about the good times, like when they fought lava snakes, and then one of them vanishes and then starts talking through the walkie-talkie, which is clearly a sign -- if the conveniently malfunctioning flashlights weren't a clue -- that his ass is already dead. Sent backward through time? Nope. Something banal. Also, their names are "Angelo" and "Christian." I mean, give me a fucking break please. It's not like there's a deeper level of meaning here.
Were I asked, back in the day, I would say that you have priests, and you have soldiers, hunting angels whose power lies in unmoving stone images, and that what this tells us is that religion is a war. And before you started yelling, I would say that "religion" and "war" are both words some of us tend to hear pejoratively but that in fact, considered on the merits of the words themselves, there's no reason to get offended on behalf of either. The Church changes, we're told. Religion, faith, is a living breathing thing that dies in the moment of its orthodoxy. A wave that never breaks, until you try to stop it moving.
The Weeping Angels are images of faith, not faith itself; like grace, or the Doctor, their true power lies in the second you're not looking for them. What each of the Companions eventually figure out is that the Doctor, God, gives you everything you need to be truly magnificent, at which point clamoring to stay with him is just a refusal to wean from the teat. Clinging to stone and turning hard yourself, thinking that there's one answer to every problem and the target stops moving. The Soldier-Priests are hunting down this lie, and not the truth: Weeping Angels are everything bad about religion, and this Church is everything good about war.