Cabin Crew - in this day and age ... yell, scream and command your customers attention!
Or follow your training, be professional at all times and don't panic people with screams from the professional CC.
It will help to offset some of the adrenalin. Because guess what, cabin crew are human
So will good training and experience.
When was the last time you told firefighters to yell & scream and worry about their adrenaline?