When we wanted to check out, the elevator door wouldn't open. At that time there was a front office clerk, but the clerk did not help when we were stuck in the elevator. In fact, he casually took care of the people who were already at the front office counter. To the extent that we are looking for an emergency elevator ourselves. I was very disappointed with the service of the front office staff on duty at that time. I checked out around 9am Frankfurt time.