About a little over half way through the episode where Ross decides him and Emily are getting married in 4 weeks because the place they wanted to get married is going to be torn down. Rachel and Joshua break up, and Monica tries on Emily's dress and Joey goes to a sleep clinic.

Ross walks into Joey and Chandler's apt. Rachel is there too. When Ross is talking to them after Chandler goes to sit down, the Magna Doodle on the back of the door is empty. Next time the camera looks at Ross, the words "Get Out" are written on it.