Door at Fort Milner

[Alice's Dream]

I'm at my 4th playthrough, still not tired of the game since there are so many options and new stuff to come around. However, it wouldn't be so fun if there actually weren't NEW things each time to discover.

I had my 2nd playthrough: the car's lights that lead to an out of script conversation with the ghosts. Then, my 3th playthrough: you can actually open a portal there. I thought maybe I could do something about it with the radio that open doors but the portal just opened, the colors are more reddish, but nothing else changed. The portal literally does nothing. Or maybe is it because I was there with Ren? Should I try another character? (Jonas, obvisouly). I expect something different for my 4tg playthrough.

It means something can be done, hopefully. The reason I keep playing even tho I mostly know all the dialog and keeping track of the letters and anomalies is starting to be a bother... is because of one specific door.

At Fort Milner, you have this place.
https://steamuserimages-a.akamaihd.net/ugc/853856987602856880/26D1B34B4D7BC628F8D992C086FA3F62C8C93F32/

As you can see, there is a light above the door, meaning it can be turned on (by the ghosts)? When looking at all the doors in game you can make the difference between doors you can open and those that aren't meant to be opened. This one is clearly openable.

At some point, depending on your choices at the end of the game while talking with the ghosts, you actually teleport right there. You can't go inside or interact with it since the ghosts are in the way. But I find it weird that the game shows you there is something inside and doesn't give you the opportunity to go inside, at the end or earlier.

Since every new game adds a way to communicate, with other Alex or with the ghosts, would it be possible that what is behind this specific door is the secret to save everyone? How many new games did you go through and at what point did you decide to stop looking?

[Sunsetter]

Is there any actual new content beyond the 3rd playthrough?
I'm going through my 3rd now, but I think I read somewhere you wrap everything up on the 3rd.