Wiktionary
press the panic button
vb. (context idiomatic English) To start to panic
Usage examples of "press the panic button".
Third thing - if the lights in Ward A fail at any time, whoever is in charge is to press the panic button immediately.
She'd known that she could not keep up the lie for long, long enough for a course of action to present itself, long enough perhaps for her to find a way to reach across her bed and press the panic button on the wall.