Actually has a rank, but you'd have to call them Admiral, since they are a Vice Admiral.
If a person is in the military, and has a rank, then that is what you call them. A colonel could be the AG, and he’d still be a colonel, not a general. I have not heard before that the Surgeon General is a military officer, I thought it could be anyone. Remember that crazy lady that was Clinton’s Surgeon General. I doubt she was a Vice Admiral.