This is just a thought.. I've been thinking hard what would have caused this lovely girl to accompany him outside the club... Going by the rumours that he had been speaking to her on a few occasions before.
Is it likely that from the few times he met/spoke to her and that he had the knowledge that she was a nurse that he played on that fact and perhaps lured her to the car by pretending to have a sick friend/family member in the car or at his flat a few moments away? That's the only reason I can see for her to leave the club without telling her friends as she would have thought she would be back very soon? Nurses, Doctors etc tend to act spontaneously because of their nature of work and caring personality?
Of course JMO and nobody can rule anything out. Her drink being spiked is also possible. She could have been feeling sorry for him, whatever story he fed her but also it seems likely that her friends could see him differently...
Just a thought.. Poor poor girl...