Continuity mistake: Richard Burton returns to his house and cannot get in the front door, because Elizabeth Taylor and George Segal came in, put the inside security chain on the door and went upstairs together. In the next scene, Burton and Sandy Dennis are talking in the front yard. At the end of the scene, Dennis turns and goes into the house. Burton and Segal haven't come downstairs yet, so no-one could have taken the chain off.
Suggested correction: Burton has already kicked in the door prior to this scene.