How pressure is manufactured

Emotion over thought.

The levers

Fear of loss, authority, a closing window, secrecy, and the promise of a rare opportunity. Scammers often ask you not to tell anyone, because a second opinion ends it.

Any instruction to keep something secret is itself a warning sign.
A real organisation will always accept you calling them back.

The pause

The single most effective defence is a delay. Say you will call back, then use a number from your card or an official site, not the one you were given.