one of my corns got out the other day. I hadnt checked on her for 2 days so Im not sure how long she was out. I found her right away though. She was about three feet away from her enclosure right next to the wall. Keep in mind they dont tend to go far when they escape and they dont like to travel out in the open (check around walls).
Now that being said, if it has been out three days that might be different but search real hard in the same room the enlcosure is in.
good luck!