It also references the events of "The End of the World", "Boom Town", "The Parting of the Ways", "The Christmas Invasion" and Torchwood episode "End of Days".
Ayrıca bu bölümde "The End of the World", "Boom Town", "The Parting of the Ways", "The Christmas Invasion" ve Torchwood'un "End of Days" bölümlerindeki olaylara göndermeler vardır.