Are we ever to learn, as viewers, how River comes to know all of this? As per this episode, the Doctor says ‘River would know … River always knows.’
Maybe I’ve gotten confused but perhaps he’s just refering to the fact River has spoilers, being as a majority of her temporal travels are in the ‘opposite’ direction?
A quick theory I thought I throw into the aether: Everyone is wondering if the ‘goodbye sweetie’ is permanent…
The Timelord afterlife is being saved to The Matrix/APC Net
River is a TimeLord, without access to The Matrix he stored her in the library.
The Matrix isn’t a permanent as you’d think… Rassilon anyone?