cool, calm, and collected

Translations
спокойный, хладнокровный и собранный
She remained cool, calm, and collected during the crisis.
Она оставалась спокойной, хладнокровной и собранной во время кризиса.
Definitions
A phrase used to describe someone who is composed, self-assured, and able to maintain their poise in stressful or challenging situations.