In a job interview with panel of 4 people and I can't seem to communicate with them properly. OMG I spent 2 days in front of the mirror practicing communication skills.

Oh fuck!

Saying stay calm would not help. Immaterial of who is asking the question always assume that you are explaining a solution to someone who does not know the domain. That will relieve you of the pressure to impress and you will put more effort into explaining the solution.