As Biff talked to the man, he noticed women getting their nails done, a bit further into the room, suddenly get a strange look in their eyes. Further back, Biff saw a number of hair-dryers (so it wasn't just a nail salon, it seemed). The women sitting under them got the same bewildered look. Then all the women got up from where they were sitting and made their way to the waiting area. As they walked, their clothing and haircuts changed, and their make-up and jewelry completely disappeared, until they looked as "man-like" as those two women he saw back at the school. At the same time, the men that were impatiently sitting in the waiting area (for their wives or girlfriends to be done with their appointments) suddenly stood up and walked to where the women had left, taking their seats as if nothing were out of the ordinary, their clothing and haircuts becoming feminine, with make-up and jewelry appearing on them, acting in a very feminine manner.
Biff looked back at the male-dressed women sitting in the waiting area and could tell that they were impatient or just plain bored, like they wanted to be somewhere else right now. One woman seemed to be checking sports scores on her phone. Another woman was reading one of the fashion magazines supplied by the salon, but she wasn't looking at fashion, per se, but rather the pretty men featured within. Biff nearly did a double take. Up until now, he thought it was only people and what they were wearing or carrying that were changing. But now that he noticed it, other things were changing too. Like the magazine, which now showed men dressing like women, as if it were all normal. And there were posters on the walls of the salon. When he came in earlier, they showed beautiful women, wearing attractive outfits and having stylish haircuts. Now, all those women were replaced by men, with the same outfits and hairstyles. Reality itself was changing!
"Are you listening to me, young gentleman?" the man asked, getting irritated, noticing that Biff had stopped paying attention to him.
Biff had to get out of there and hide himself away somewhere! Who knew what kind of changes could happen if he stuck around?