- don't ask them any questions, just do the tour, ask if they have questions answer them will as little details as possible. When they say they have no more questions, tell them you have other interview scheduled and you have to take your of your daycare kids before they get here (if during dc hours) or just say you have to get ready for them. Thank them for their time and walk them to the door. don't waste your time if you know you don't want them. But keep in mind that all the people you interview might know other parents looking for care, so if they feel rushed or that you don't care then it will give you bad word of month.
I would just do the whole interview for the practice and hope for good "word of month" at the end. But that's just what I would do.