The fact that smoke wasn't rolling out from under the apartment door was a good sign. The fact that she didn't hear alarms blaring from the other side of the apartment door? Also a good sign as far as she was concerned.
She didn't know what type of scheme Clint was cooking (or what he was literally cooking) but she thought she was prepared for anything. She had brought a bottle of wine, and some store bought cupcakes. She had figured they were staying in so she had dressed casual like, so as she reached up and knocked on the door she just hopped that when the door opened it didn't revel some sort of disaster.