The stairs to the Summit generally only appear as an elevator in both the Dark Passageway and that one big processing room where you have to fight either a bunch of Bandits or Old Guardians. As to how you managed to go back to floor 0 from the Summit? No clue.
Ugh. I did find a thing marked 'elevator halls' that seemed to lead to a big doll processing room. Lots of conveyer belts.
I think I was just walking around in circles for a long time tho.
As for me accidentally leaving thensummit and getting set back to floor zero, that might have been a bug then.
If so, it sucks.
If she summit is supposed to be a 'home base' or a safezone, maybe you should have a fast-travel option to always go there. Or an elevator in the perk-choosing rooms between floors.
As is actually getting up there to see your collection is a fuckin struggle.
Edit: Started a new save, found my way straight to it through 'dark passageway', the Egyptian/mummy themed mini-floor between floors.
Not sure how i'm going to get back after I leave, but you can at least walk around up there and store the couple of people I captured so far.
It's kind of a shame there's no option to play with people once they're locked into bondage. For being a bondage-themed H-game with an orgasm meter, it's pretty coy about actual sex stuff.
It feels like it's missing an obvious mechanic to toy with your prisoners to raise their opinion of you, which would let you make them into servants.
Instead, nothing you do seems to effect their mood?
Also, there isn't really much of use to the player up in the summit either. a bed, some food.