panic button

hit / press / push the panic button {infml} (to react to a situation by demanding emergency action; become excited; panic) — паниковать, запаниковать; поддаться панике, впасть в панику, поднять панику

If a person hits / presses / pushes the panic button, they let unreasonable fears make them react to a situation in an extreme way

Example: Despite two consecutive losses, our coach isn't about to push the panic button. (CID)

Example: Stay calm; there's no need to hit the panic button.

Example: But he has made it clear that hitting the panic button is the last thing on anyone's mind.
(Wake-up call for us: Brett by Huddersfield Daily Examiner)

Related vocabulary:
[pile on the agony]
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panic button a button or switch that operates any of various safety devices, for use in an emergency — тревожная кнопка; кнопка сигнала тревоги