Julia Swales
Julia Swales was one of Martha Jones's friends and a trainee nurse at the Royal Hope Hospital. She was one of the people trapped there when the Hospital was taken to the Moon and was terrified. (DW: Smith and Jones). She was still friends with Martha a year later, when she was working on the CERN machine in Switzerland. She warned Martha that there were problems before being kidnapped. She was later rescued by Martha, Jack Harkness, Gwen Cooper and Ianto Jones. (BBCR: Lost Souls)
In Turn Left, the timeline where the Doctor died, Sarah-Jane Smith and her friends would investigate the hospital and the oxygen would run out. This caused everyone in the hospital,including Julia, to die of oxygen suffocation.