This is my definition for expert:
“Expert is the one who can finish the job quickest with the smallest number of flaw”
By saying “finish”, I mean the result must meet the required quality.
About the “being calm” part of yours, I have to say that I do not 100% agree with you. I’m not an expert, but when crisis happens, I have 2 choices: being panic and find the solution or being calm and find the solution. The latter definitely brings the better result, so why not remain calm?