Unless otherwise provided, any party may take the testimony of any person, including a party, by deposition upon oral examination or written interrogatories for use as evidence in the hearing. The deposition of a commissioner, the executive director, or other staff, may only be taken upon application to the commission, for good cause shown, and only in those circumstances where the statements or depositions of other staff members would not reveal the information, evidence, or details needed by the party for the case. The attendance of witnesses to a deposition may be compelled by use of a subpoena. Depositions shall be taken only in accordance with this rule and the rules on subpoenas.