If you want to mirror the interviewers style you can:
Mirrow your tone of voice with theirs. If your being interviewed and the interviewer is speaking soft and calmly, matching their tone is going to help them relate to you. People like people who are similar to them and they then trust them easier.
Make sure your body language is positive. It's important to remain and come off positive regardless if the interviewer seems differently. Makings ure you have a positive attitude allows you to come off as friendly.
The third way you can mirror the interviewers style is to make sure you are focused regardless of how distracted the interviewer may seem. Listen to what they say instead of watching what they do.