First of all.

I do not own this theory in any way. if anyone else theorized this i do not own it. all of what im about to say is just a guess in my head.

Ok lets move on.

after beating night 5 on jolly 3 chapter 2.

we hear kevin johnson talk to us using an old memo of some sort. while listening further we hear this.

"You can also access that fancy bathroom down there"

by what he means by fancy bathroom down there. we see at the end that we go DOWN an elevator to a deeper facility.

"Down there" just think about it.

everything in those teasers show that the place is just filled with high budget stuff. take a look at those teasers.

"Fancy bathroom" And jolly 4's facility as it looks IS fancy.

At the mobile at the main menu. the audio log 4 or 3 shows that testing metalionnete's fire system.

didnt go as planned. the facility alarms go off.

im speculating that it happend BEFORE jolly 3 and thats why the facility looks burned and all.

OR it happens at the time where jolly 4's trailer takes place.

( where the facility just collapses and stuff idk lol )

and after the protagonist enters the elevator, theo calls him.

after then the elevator collapses? or falls back down.

this is where the how jolly 4 started theory comes up.

and after that the protagonist goes unconscious and after maybe a few hours or so he wakes up.

point click blah blah blah he looks at the place and everything is destroyed. he finds light and goes towards it and then he enters the "fancy" facility.

then blah blah blah finish what he started.

we may not play AS the j3 protagonist thats all i have to say by then.

this is just by theory. bye