Nevada Badlands Locked Area

[Hoopla]

I noticed there is an area underneath The Breakfast Club that is a question mark and I can't get to it. It's just a vault/blast door with no way to interact. Is this part of the story later or a secret area? Currently the location I am in tells me that I wont be able to do any side-quests or backtrack to another area if I proceed.

[Cat]

It's unlocked later, story locked.