One of mine can escape from a harness in about five seconds. It's pretty amazing to watch.
She’s escaped a few times. Dangling a feather in front of her or using a laser pointer brings her close enough to reclaim. We’ve since bought a ‘cat gazebo’ - a small mesh zippered ‘tent’. She seems to like that. Though, once, my husband went to bring her back in and she zipped away from him, across the yard, caught and killed a mouse, and ran back into the gazebo to enjoy her catch!