There are two known reasons Springlock failures can occur, one of these is when the springlocks interact with water and moisture, for this reason employees must not wear the suit in rooms with too much moisture in the air. When the suit is in animatronic mode, it is limited by it's programming, as can be seen when Springtrap was able to be led around by the sound of a child's voice.
It is, however, possible to escape the suit before the injuries become fatal as shown by William in the novels. This causes the endoskeleton and gears to spring into its usual position, anyone caught inside the suit when this happens will be impaled and crushed by the parts. These incidents occur when the locks, that are holding the endoskeleton in the folded position, break. A 'Springlock failure' is one of the many incidents that has happened at Fazbear Entertainment restaurants over the years.
