This generally happens with everyone. It used to happen to me as well initially when i used to be for behavioural based interview. Remember one thing in mind you are being judged on basis of your communications ability and also on your facial expressions. So stay calm dont panic and while giving an interview give attention to all the interviewers but just think that you are sitting alone with one persn in the room. The key factors to answer the question are : Situation, Task, Action and Result. Keep this 4 things in mind and prepare your answer according to that. Give more attention on the action and result part. use the words like "i decided to do this" , "My decision in that situation was this " . And the outcome would be marvelous. You will have rocked the interview.
