Race Against Time (in-universe)

According to one telling of a source, after a human fell asleep in the TARDIS after joining the Sixth Doctor to stop the Rani, the Doctor woke them after the adventure was over and dropped them at their home. (NOTVALID: Race Against Time: Marker 152) As they arrived they were greeted by a delivery-boy who gave them a package. Inside was a book titled Race Against Time. If the human decided to open it, (NOTVALID: Race Against Time: Marker 153) time paused around them and the TARDIS yet again arrived, apparently restarting the day. (NOTVALID: Race Against Time: Marker 1)

Behind the scenes
The Make Your Own Adventure with Doctor Who novel Race Against Time begins with the protagonist opening "this book," which causes time to freeze around them as the TARDIS arrives. It is not until the "bad ending" of Marker 152-153 that some clarity is given, as the main character is delivered a novel named Race Against Time. If the reader chooses to read the in-universe novel, they are told to return to Marker 1.