Who said "Paranoia is a natural response to danger."?

This quote is attributed to Armstrong.

Paranoia is a natural response to danger. - Armstrong

"Paranoia is a natural response to danger."

Armstrong Fear

Character in And Then There Were None

Buy "And Then There Were None" on Amazon

"We are none of us infallible."

"The innocent suffer with the guilty."

"Each of us has something to hide."

"We deserve what comes."

"Face your fears with courage."

"You can't live your life in fear."

"Snakes. Why'd it have to be snakes?"

"Fear is just another obstacle to overcome."