"The cracks in the skin of the universe - don't you know where they came from? You don't, do you? The Doctor in the TARDIS doesn't know... The universe is cracked. The Pandorica will open. Silence will fall."
It's good to know there are more cracks than just this one, because that means the issue is parallel-related, like the Void, and that means timestreams and timebubbles and all sorts of fun things. The Pandorica, that sounds interesting, like Pandora's Box but crossed with a calliope. Silence is probably a proper noun, if my instincts are right. Of course, she could have said "Medusa Cascade" and "Whatever Schism" and "Shadow Proclamation" and we could be in any other season at all. Having had it both ways I must say that I do hate being unspoiled with this show, because in writing about it, it's easier to plaster over the horrible bits and focus on the point when you know what the point is.
Maybe there's more, but right then one of the fifty brilliant plans starts happening, and all of Jeff's team are sending the ZERO message everywhere, and the Atraxi are suddenly alerted. Zero points out that they still can't actually find her, and then something neat: The phone he's using, Rory's phone, contains pictures of all his comatose bodies. I didn't see that one coming. The Doctor congratulates himself -- "Who da man?" -- and immediately thinks better of it. This one time.
They discuss how Zero's out of options, but then suddenly she doesn't need coma people, she can just put Amy into a coma, because they were housemates for so long. So she does that. More creepiness, though: She takes the form of the Doctor, which confuses him until little Amelia steps out from behind him, grinning horribly. She's dreaming of the Doctor, in her coma, just like she's been dreaming her whole life. That's how bad he hurt her. The girl who was pragmatic enough, but still vulnerable enough, to pray to Santa: He's the Crack.
The Doctor says no, and because he's always right I guess he's right, but he thinks that she's dreaming of him because she can hear him talking in the room. (Which, how come that didn't happen with everybody else?) So he starts yelling at Amy to remember the house that time, the secret door, and what she saw when she went in. More flashy-flash memory stuff, and Zero takes the form of Zero. The snake with the teeth. That's pretty brilliant, as well. There's so much going on it's hard to fit in context, but looking back there are lots of neat moments here. So the Atraxi teleport Zero out of the hospital, and she hisses one more time: "Silence, Doctor. Silence will fall."