Yet when his apartment was hollowed out and renovated (and his boxed and boarded pieces probably dumped somewhere) in Dreamland II, Mulder just... moved on. In a way, his bedroom was cluttered up by an existence he didn't live-- papers and gear and a four-poster bed-- and, once emptied, provided him another habitable (if still simple) space to exist in. A proper pillow, a proper sink. And he chose to live there, which is interesting.

Season 6 in general was Mulder's year of domestication: forcing him to ground, pair bond tighter with Scully, confess his love to her, sneak case files or hack emails or drag her to Florida or invite her on a date-- in short, to reinforce how important she was, not just their partnership. And while some cosmic force, fate, or freewill gave him this choice, bam!, along came a bedroom. One he simply moved into.

This post has escaped your original question, so I'll reel it back: why is Mulder prone to hoarding?

The one place we see Mulder's true hoarding tendency manifest is where he actually lives: the basement. Mounds and stacks and pockets and spaces and jammed crannies and crammed histories. There is his passion.

And in a way-- I suspect-- Mulder's not really a hoarder so much as a man who's forced a lifetime, with all its incumbents, into a small office tucked away in the bowels of a basement. Same with his study in I Want to Believe. Same, if I recall, with their house in the Revival (or S10, at least.) What we're witnessing is a man boxing himself into the safest, most intimate corner he can-- away from prying eyes-- and filling that space to the brim and overflowing. Until Scully expands him, frankly.

That, and he's messy.

"BUT YOU SAVED ME"

During their professional review, Scully takes the fall, insisting she'd hindered her partner, led Mulder astray-- a belief that has been haunting her since his loss of faith (post here.)

Their office is burned, their lives have become passionless grunt work.

But on her way out, she leaves the door metaphorically open for Mulder:

"Maybe you should ask yourself if your heart's still in it, too."

An invitation to join her, come with her, if he chooses.

When Mulder doesn't respond, she lingers in the hall, alone.

That night, Scully lies in a two-person bed, the camera panning slowly over to the empty side where a pillow remains.

Alone. Perhaps ready.

When Mulder knocks, she lets him in; when he slurs over his words, she asks,

"Are you drunk, Mulder?"

Perhaps ready.

When he deflects with a joke (a half joke, but she doesn't know), as always--

"What exactly are you implying?"

--Scully drops her head: another gentle rebuff, she believes. Mulder wants her for the work... and nothing more.

"Go home, Mulder. it's late," she says, weary.

Still, she comes along. She stays.

Until they fail.

She failed him (Scully believes.)

If she could have helped, at least it would justify staying. Instead, it's yet another sign she holds him back. Now, his one devotion might never be returned to him.

Now, she believes, he'll have lost it all.

Perhaps if she leaves-- takes full blame-- at least he will be no worse off. Mulder might even be able to crawl back to the basement someday.

When Scully announces her departure and begs him not to make this hard-- don't fall apart, don't give him fuel to talk you down, help him let you go or else he won't--she suspects he will follow.

When he does, she prepares for a fight. Mulder has never let go easily.

What she doesn't expect, what she hadn't hoped for, is his all-consuming devotion--

"But you saved me! You've kept me honest ... you've made me a whole person. I owe you everything ... Scully, and you owe me nothing."

She is what he needs. She is his salvation.

So, she believes.

And he proves her beliefs by going to the ends of the earth for her.

And she proves his by saving him.

And they go on proving them to each other.

CONCLUSION

Bonus: Fight the Future Hallway: In-Depth.

Companion piece to this post.

Thanks for reading~