Today, around midnight, I woke up with that thought on my mind, but I remembered the dream perfectly.
It started with River Song, in one of those standard "keep the room dark so we can't see the big bad yet" scenes. Said big bad has some sway over her (the specifics weren't made clear), so while she protests a vague, unstated action the big bad's demanding of her, she eventually concedes. The last words in this scene, from the big bad, are: "You have to kill him," with the camera focused on River's tormented expression.
Cut to: the Doctor (eleventh model) at some kind of fancy party; through conversation, we learn that he's speaking to a president of some kind (presumed to be a future US a/o Earth politician). Someone attempts to assassinate the president, destroy the building the party's in, etc etc. The Doctor and the president start running through the building, ducking behind ornate decorations every once in awhile to avoid attack.
They finally get to the TARDIS - which for some reason is a giant blue barrel - and hop inside, joined by several other people (including Rose, River, and Craig from The Lodger), who begin singing the Glee version of "Lean On Me" as they pilot the TARDIS.
Yes, really. They've apparently saved the day by making it to the TARDIS, and feel like expressing this in song. Rose takes lead vocals. It's all very heartwarming.
Then, just as the song reaches its climax, River pulls out an antique pistol and aims it - at either the president or the Doctor, it's unclear. She apologizes several times, the Doctor notices what she's doing, pulls out the standard "No, no no noooo!!!" he's fond of, and the screen (so to speak) goes black.
A shot is fired.
And then I woke up.
My second thought after waking up was of another scene entirely. This one more based in canon:
Doctor: [nervous around the BABY, carefully cradling its head while looking for someone to shove it off on] Uh, that is - River! River's here, here, River why don't you... [shuffles the BABY around in his arms] why don't you hold the baby?
River: [smiling sadly] I can't.
Doctor: [puzzled frowny face, you know the one] What do you mean "can't"? It's a baby, look, even I can hold a baby -
River: I can't. It's like... oh, what did you used to say? "Don't touch the baby?"
Doctor: [continued frowny face, then shock/disbelief] No. [looks between BABY in his arms and RIVER standing next to him] No, you can't be -
And my thought about this scene was "That makes more sense than the dream I just had."
Which, of course it does, but my brain apparently decided this really said something about how bizarre that dream was. I don't know! It may be my brain, but I can't tell you what it's thinking sometimes.