So We/most of us know that The story continues when the J3 Facility Started To Collapse (aka, The Secret Ending)

As we know at that time when collapsing, we see a withered Jolly mask on the ground, basically how Eric Took it off. and then we are shown a basic gameplay of free-roam version of J4- so what I'm thinking in my mind is that the true ending is , basically the secret Ending (Again) After Theo/Us finish investigating the warehouse, There was a earthquake for a bit and stop, which makes Us/Theo/The Nightguard Of J4 leave immediately. At that moment the warehouse exit doors were locked tight by Jolly, Etc and our way out is the door right behind The 1st floor office. But it is locked tight so we need to get a key first and led you to the underground/Basement. We will see a big door like most of us have outside of our houses. We are going to open it and escape eventually.... This doesn't make senses but I hope y'all respect my guess. Peace Out