From Inside the Grey House:
Natalia went into the building, acting as if she belonged there. The back door didn’t have a lock. Inside the building, Natalia went right for the stairs. She didn’t want to get stuck talking with an overly curious passenger in the elevator. Though this was a large apartment complex there were only four stories and only eight apartments per floor. In her other visits, it seemed as if the residents knew each other. Taking the elevator was never a good idea. Jeffery Tathers lived on the third floor; using the stairs didn’t prove much of a problem. On the third floor, she headed down the hall toward his apartment, digging out keys as if she were headed to her own apartment. In front of his door, she quickly took a look around, making sure no one was in the hall. She used her lock picking tools to unlock his door then slipped into his apartment and shut and locked the door.
Cat Stark 