[2019] Did I find a secret mission?

So I was wandering around earlier and was prompted to solve a riddle at an observatory. I ended up solving that riddle, which wasn't super hard, and unlocked a secret room that led in to an old OSS bunker and then back out to the surface. In that bunker, I found a pretty sweet outfit (picture at the end).

After that, I was prompted for another mission called "G Phillips Protocol" or something to that effect. I get there and it's just a hallway with a few doors, one of which had a shootable lock on it. I got in and only it led to a basement room with a box and Outcast cache in it.

Now, I could be totally bonkers, but it seems like there should be something more to this, like some sort of easter egg. I've tried everything I can think of to open the door in the back, but to no avail so far. Maybe I'm wrong and this isn't a secret mission and there's no easter egg.

I can't find anything related to this mission online so I come to you for help, fellow agents.

Here's a picture of the room and the outfit

EDIT: The location of the start of the mission was at in Foggy Bottom, around -1234, -320

The location of the hallway with the basement room is also in Foggy Bottom, around -1377, 48