Handling requests for water during the interview
There may be several interruptions and requests coming from your subject during the investigative interview. A common request is the desire for a drink of water. Remember, you should never deny basic rights, such as a drink of water or use of toilet. Denying such rights may alter the view of the conversation as being voluntary.
You should always satisfy this request, but at the same time maintain control of the conversation. Imagine this, it’s like your subject is trying to call a timeout. In sports the coach calls a timeout to stop the momentum of the other team and regroup. You don't want them to call a timeout and stop your momentum. Let the subject know that you have a couple more things to go over and you will make sure they get that drink of water. After a few sentences to complete your thought, ask your subject if they still want that drink of water.
Having planned ahead, you will have a bottle of water and small paper cup out of view and ready to go. Reacting to the request in this manner, you maintain control of the conversation, whilst satisfying their request and mitigating the disruption to the conversation.