Nora hadn't come down off of the sofa until Jaune came to relieve her. Normally she was very brave, but when it came to these sorts of things... really, it'd startled her more than anything else at first, but then she'd started thinking about the mouse. The mouse crawling around, climbing over her feet, using those little claws to scramble up things... and she'd freaked herself out even more.
So when Albus volunteered to come take the mouse away, and Jaune offered to bring her a coffee and save her from the sofa? She jumped--figuratively--at the chance.
The front door was unlocked, so Jaune was able to let himself in, and save Nora from the sofa. She didn't climb down until he gave her a hand, and then she hid by the open front door, thinking maybe that the mouse would let itself out by the time Albus came to collect it.