As Jack opened the door, Buffy was still expecting a trap. Once inside the expansive, empty space - she was starting to think differently. Which made guilt gnaw at her a little. But she still had her reasons for being paranoid and on alert. People always wanted to kill the Slayer, and right now she was more vulnerable than she'd been in...ages. (Ever?) So it was a prime time to mess with her. She could tell Jack felt betrayed, though. Which was actually a good sign. It meant that maybe he hadn't been lying.
...Which made her a total bitch. Not like it was her fault, though! Like she could just know that she had an alternate Buffy running around? Tcha.
"It's...big," Buffy said as a way to pass conversation. "Dark, too. And it kind of smells like...maple syrup?" Huh. That was weird.
"Still weird to have Angel Investigations without Angel," she said to Jack. Buffy looked up the staircase, and down a hallway. She almost expected Angel to jump out and tell her this was one massive joke and he had the answers to everything going on, and that everyone back home was fine. After all, this was his city. "So who the hell is this Peter?" she finally asked.