Why Isn't Everyone Awake?

Jerry and Esther were at Dale's home in Dallas, Texas. They had spent their second night and it was the morning they were to arise and be on their way to Springfield, Missouri by 7 a.m.. Jerry said he awoke about 5 a.m. in the dark, hearing a strange sound. At first he was confused and couldn't figure out what it was then he realized it was someone "tinkling" on the piano. He came out of his room just in time to see Dale, slightly annoyed, asking Esther why she was waking the whole house up at 5 a.m.. She knew the clock said 5 but she got confused and thought she needed to add 2 hours to the time. So, she got creative and "tinkled" on the piano until it was loud enough to wake someone up.