After the mules disappear, Festus walks toward Doc and Kitty, who are standing outside the Long Branch, and a boom mic shadows appears on the Long Branch sign.
When Festus runs in to tell Matt that Sweet Billy and the others are going to hang Pony Beal , they run out the back door of the jail. Festus jumps on his mule, Ruth, and Matt runs off-camera to get his horse. But when they get to where the hanging is about to be, Matt and Festus are riding double on Ruth.