Simione was having a hard time with the dress Lucy had her wore. It's definitely not her size but she had no choice then but to wear it since her clothes were accidentally messed up by Lucy's personal assistant.
It was the weekend, she had no class or work and so she decided to drop by at Lucy's photo shoot only to end up getting an errand for her. One of Lucy's glam team employees got sick and was not able to pick an important jewel she was to use in one of her shoots so she volunteered to pick it for her. Before she left, her dress was ruined and so she had no choice but to pick up something in Lucy's wardrobe on the photo shoot site.
When she arrived at the store, there was a close sign in the door. However, the store already informed Lucy that they would close the store that day but that she was welcome to send someone to pick up the parcel. So despite the close sign, Simione went inside especially because the door wasn't locked.