Problems with housebroken dog?

Ok so I was getting ready for a party at my friends house, and she has this almost 2 yr old chocolate lab. We were sitting in the kitchen and she just peed all over the floor. She has been housebroken since she was a puppy. Usually when she has to go she goes to the door and barks, but she didn't do anything like that. And then we took her outside and she did it again. What's up with her? I know she's fine, but any ideas why she just blew off all her training?