Before Tardis showed up she explained her situation to both of the princesses so they could were figuring out what to do. While they were taking Tardis found book on teleportation and apparently has the Doctor's speed reading trait in this world. The princesses decided to let Tardis to go see Twilight about this so she can help with situation. Tardis asked to specify where Twilight is and decided it would be the perfect opportunity to test out the new teleportation spell, but she is personally not really believing that the world has magic. It most likely something else that hasn't been fully explained yet so they call it that. While the teleportation was successful she had a feeling that the way she did it was not considered normal here after seeing the princesses reactions to her signature way of disappearing and reappearing.