Lost Pet: Harley

Circumstances

My husband took out the trash at our apartment complex around 8 pm and Harley snuck outside without him realizing it. He came in and shut and locked the door. I had went to bed already so there was no one to hear at the door if she was meowing or scratching to come back in, like she had one time before. It is now 4.5 hours later. I looked all through the house with the cat treats calling her name and no response, I looked outside and called her name several times with the treat bag. No response. She is probably hiding somewhere from other predators.