After the initial shock she regained/recovered her 'composure'.
She never loses her 'composure'. [=she always appears calm]
He kept/maintained his 'composure'.
(..) Consideration... Consideration. Will... Have you heard about things like that? Choucas, we allow you to work, providing a royal composure, even if you forget what you shouldn’t do. But I won't advise you to abuse it. Do you understand what I am talking about? This is not a case of panties. (..)1981 To Kill a Cop