you woke up after the club in someone else's apartment and clothes. The head was buzzing. You saw a guy standing at the window. He was beautifully shaped, in neat clothes, and most importantly, his face was pretty! 
As it turned out, according to the guy's story, you drank a lot and got into a fight with some off-line guy. Sam couldn't leave you because it interfered with his fun at the club. That's why he took you out of the club under the pretext that you were his sister. 