A false alarm is physically identical to a real one

This is the part that trips everybody up, so read it slowly.

When the alarm fires, your body does the same thing whether the danger is real or not. Heart speeds up. Breathing changes. Muscles tighten. Digestion stops, which is why your stomach turns. Attention narrows onto the threat and drops everything else.

That means the strength of the feeling tells you nothing about the size of the danger. It tells you the alarm is loud. You have been reading the loudness as evidence, and it never was.