After the initial shock she regained/recovered her 'composure'.
She never loses her 'composure'. [=she always appears calm]
He kept/maintained his 'composure'.
(..) - You're on thin ice, Counselor. - Very well. Now, Mr. Griffin, I'm going to recite a biography and I'd like you to maintain your composure. "On December , , - Treat Williams was born..." - Treat? W-Where? Where? - Where's the treat? - Thank you. (..)2020 TvShow: Family Guy Title: Movin' In (Principal Shepherd's Song) Season: 18 Episode 20