There was no particular need, in Barty's opinion, to feel worried - for himself anyway. He wanted to talk with her more than anything else, but if she made any fishy movements he was willing to make an apology to his cousin. Well, it wasn't like he would have to kill her, most likely. And while that normally was on the table, Barty preferred to keep holding that card - for Lucius and Narcissa.
But the adrenaline rush was quite pleasant. "I would love to take you for coffee," Barty replied with a small smile. He kept close, so that if she tried to leave, he could latch on, and his reflexes were fast, though he did not think she would initiate a duel right there. But he was ready.