People
Arthur had adopted his normal crisis role, which was to stand with his mouth hanging open and let it all wash over him.
— Douglas Adams • Life, the Universe and Everything

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
Arthur responds to a crisis by standing in stunned silence and letting events pass over him. Calling this his normal role makes inaction sound like an assigned duty. The joke gives his helpless response the familiar shape of a well-practiced routine.
Context reviewed