Slip something in her drink

I let my attention drift off to the music, but kept watching to see if she was a cheaper version of the other hookers. I sat there nursing my drink and just watching the comings and goings on and around the bar, but every time my attention was drawn back to the woman. I was about to leave, when she stood and walked to the restroom. I didn't really pay a lot of attention to the man until he bought her another drink and slipped something in it. Now that peaked my attention. I was witnessing a sleaze bag attempting to drug a woman. I'm not naïve but I didn't want to get involved. I waited for her to return to see if she would accept the drink, or if she was smart and refused it.

To my surprise, she accepted it and took a drink. I didn't know what he used, but it wasn't long before you could tell she was feeling the effects of whatever drug he laced her drink. Now I was having a moral dilemma. Do I step in and make a scene or just let her pay for her stupidity. I'm not a white knight by any means and fighting is not in my nature. I ran several scenarios through my mind as I tried to figure out what to do.