Be honest. If you are comfortable in different roles, point that out.
Emphasize benefits to the organization. Things like, determination to get the job done and work hard but enjoy your work are good.
Be sure that you refer to something that was beyond your control. Show acceptance and no negative feelings.
Talk about having fun by accomplishing something for the organization.
Always have some questions prepared. Questions prepared where you will be an asset to the organization are good. How soon will I be able to be productive? and What type of projects will I be able to assist on? are examples