Fridge / Doctor Who S32 E1 "The Impossible Astronaut"

• It's revealed at the end of "Closing Time" that the Silence have erased River's memories of them. We are never told exactly how much they messed with her head, but it must have been fairly extensive. If you think about it, and paying close attention to River's behaviour in this episode, at the beginning of the episode she doesn't remember the significance of Lake Silencio or that she is the astronaut. She only remembers after unloading her gun in the astronaut's direction, which is why she says " . . . 'course not." after the astronaut descends into the lake. Because of the large-scale memory tampering River's been victim to, it is also entirely likely that, at least for this episode, she doesn't remember that the Doctor found a way to fake his death. Whether she remembered that information during the three-month Time Skip is up in the air, however.
  • Not only that, but it's an established rule that when different versions of the same individual are in the same place and time, they all inevitably forget some or all of the events in question. Psychic meddling aside, River may not have remembered that was her until after the astronaut had walked away. Of course, if she hadn't and knew who she was trying to kill, that leads to some horrifying implications...
• Something River didn't notice due to the emotional turmoil is that the letters are actually subject to the same fixed time loop as the Doctor's "death"; the younger Doctor is summoned to a diner in Utah, where he encounters the Ponds and River who, unbenownst to him, have just seen his 200 years older self die at the nearby lakeside which he figures out over the course of their travelling. Thus when it's his turn at the lake he has to send the letters to ensure his past self and companions meet in the diner, no different to the fact the he has to be shot by the Astronaut, it's just no one else knows he's wearing the tesselecta at the time.
• While it is funny Take That! moment it is perfectly reasonable for Doctor to panic once he's reminded that those are Americans pointing guns at him. He already died like this.