He writes a touching letter to his patron, imploring him to let him go, and promising never to betray him.
The scene where Falkland refuses this is the most highly wrought in the book.

He says to him, "Do not imagine that I am afraid of you; I wear an armour against which all your weapons are impotent.

I have dug a pit for you: and whichever way you move, backward or forward, to the right or the left, it is ready to swallow you.

Be still! If once you fall, call as loud as you will, no man on earth shall hear your cries: prepare a tale however plausible or however true, the whole world shall execrate you for an impostor.

Your innocence shall be of no service to you.