Both Uses of

retract
in
Misery, by Stephen King

It had fallen in some way that was keeping the lock's tongue from retracting completely.†
Chpt 1 *

A little more ....a little more ....In his mind he could see the rocker beginning to move in its dusty little alcove; he could see the lock's tongue begin to retract.†
Chpt 1

Definitions:

(1) (retract)
to take back; or to move back or in
in various senses, including:
- to take back something previously said -- such as a promise or opinion
- to move back or in -- such as an airplane's landing gear, or pulling your hand back after being burned
- in surgery, the use of a medical instrument to draw skin or an organ back out of the way
(2) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

Less commonly, in phonetics retract references changing the sound of a vowel by pulling the tongue back.