Are you sure that it was the 3rd floor? I encountered a guy fitting your description, he turned around surprised and said "What!?Don't talk to me out of the blue like that! I may fall in love with you!" Or something along those lines. I tried talking to him again and he said "Wh-what? I haven't fallen in love with you." This is a bit creepy because I'm a guy(no I'm not one of thise guys that pick their characters female).