Well, not specifically them, but that episode of Dr Who.
I just don't get it!!!
Please someone explain to my thick brain the time lines of it all.
If the Doctor hadn't met River Song at that time, how did he know that her life was going to be in danger, and give her a sonic screwdriver (to be given back to himself) in the future?
Do you know what I mean? If at some point in the future, when they are 'together', he gives her this sonic screwdriver because he knows that she/he'll need it in the library. So he must have experienced the whole library thing.
Sigh.