Could they have broken the lock?
It’s a pretty heavily fortified entrance. I’m in the trades and can be somewhat of a brute, and their entrance is something that even i’d have a hard time contending with, even given enough time. The street she’s on is one of the busiest blocks in chinatown and a block away from the police station as well, so i doubt it. They might have just pushed their way in behind a legitimate customer or they pulled a 42 fake and used someone as a fake customer for her to buzz the door open is my best guess.