[keep] a level head

to stay calm and sensible in a stressful or difficult situation

The origin of the idiom "keep a level head" can be traced back to nautical terminology. In sailing, a "level head" referred to the situation where a ship's compass remained level and steady despite the vessel's movement on the water. It symbolized stability, balance, and an accurate sense of direction. It is often invoked during times of stress, conflict, or uncertainty, such as in high-pressure work environments, intense negotiations, or personal crises.

She keeps a level head during high-stress meetings, calmly addressing challenges and finding effective solutions.
He always keeps a level head in emergencies, efficiently assessing the situation and taking appropriate actions.
Despite the chaos, she kept a level head throughout the crisis, guiding her team with clarity and composure.
They will keep a level head during the upcoming negotiations, staying composed and advocating for their interests.
If you want to succeed in high-pressure situations, you must keep a level head and approach challenges with a clear mind.