This is lore coming from the books, where he tears the robots down for “reminent” or something like that which somehow causes you to become immortal (I mean, if children posses the suits they were stuffed in, this isn’t too far fetched for the story), why he didn’t get their reminent right after killing them, I have no idea, maybe it only worked after they possessed something, idk, but either way, doing so caused the spirits of the kiddies ended up loose, and then cornered Afton down to a room, in which (I forgor whose spirit in specific) starts to chase hi around in. Now I didn’t mention this before, but I will now, Afton lured all the kiddies he killed by dressing up in the spring Bonnie costume, of which was a spring lock costume, which allowed for the robots endoskeleton to be removed and some stuff to be cranked back for enough space for a worker to get inside and preform, with also a huge risk of dying a horrible death.
This very suit was in the room he was getting chased into, and for some reason he put it on for protection or something. Now, to explain it fully, animatronics have and endoskeleton of which has all the functioning stuff, and since the earliest version wasn’t as advanced as the others, and didn’t have the same fudged, they decided to make a mechanism of which all the things that hold up the endoskeleton in place can be cranked back with springs, for a human to preform in. The problem is that these can possibly snap shut, it’s like putting your fingers on a spring, and if you slightly move one, it will spring out and fling out. In this case, the ‘out’ is being covered by a humans body, and the spring is connected to the suit, and the springs can be tripped by moisture, due to the friction between the spring getting slippery.