Your answer can best be framed along the lines that you are interested in the underwriter role and seeing how you can provide suggestions on efficiencies in the role, opportunities for expanding cross-functional collaboration, being a super user and subsequent trainer of new hires. If you are interested, being a resource for future college outreach/recruiting, may also be attractive to a rapidly growing company.
"First of all I would like to say that I understand the requirements of the company and also that I know what might be the expectations from this job. I would make sure that I add value to the company through my presence and work. Also, if needed I would love to volunteer my services as and when needed for any other tasks including training the interns, giving presentations at some other locations on behalf of the company, doing any voluntary work. I will make sure that I understand the company's culture and become an integral part of it and help it in future growth."