Calm spreads faster than panic if someone is brave enough to go first.

Groups copy whoever seems most certain, and that is usually whoever is loudest and most frightened. It does not have to be. One person speaking at a normal speed and doing the next obvious thing resets a room surprisingly fast, because everyone else is hunting for a signal about how worried to be. Being that signal requires no particular authority.

In the next situation that starts spiraling, slow your own voice before you say anything. Name the next step rather than the problem. You will not feel calm while doing it, and that is not required.