sorry but i'm already go in, after that the guy in that room run away and idk what to do next
there was a bit of a discussion on that already. there's a building to the top right of the same map that has the entrance to the dungeon that you have to go to and talk to some guy during the day
but apparently if you're on the translated version (at least versions 2 and 3 since I haven't checked version 1), the guy that's supposed to be there was accidently deleted from the map.
This means there's no way to complete that quest, and no way to get ending D. He is properly there to finish that quest though if you play the untranslated version, which is sadly newer and you'd have to replay up to that point.
EDIT: Can confirm that this guy is here in front of the door on version 1 of the partial translation
going to look into things a bit more by messing around between the translated versions, but it's definitely impossible to do that quest and get Ending D w/o him at that door.
Besides, seems like you don't need to do ANY of the dungeon past the 3rd floor in order to get endings A, B, or C since everything needed for ending C is still right there on floor 3 and you don't lose your virginity by talking to the guy that gives access to materials for some quests
EDIT 2: Starting up versions 2 or 3 of the translation gives this error:
that's probably due to the guy for Vagina's 2nd quest not being there, but i could be wrong. So yeah, you probably do have to play up until finishing that quest on either version 1 of the translation, or playing the original japanese version
EDIT 4: sorry for all the edits, but looking into this even more, you can't talk to the guy in front of the house AT ALL on translation versions 2 and 3.
only other test is to see if you can even do the quest after moving a save between the different versions, but I'll need to make progress on the versions first
EDIT 5:
That sucks. Guess partial players can't complete the game then. Partial save file doesn't work on untranslated as well from what I've found out. Also that image, you're supposed to interact with the purple mushroom. If that doesn't work then its broken as well.
alright, through some testing, came to find out that you can complete that quest, but only if you use the first version of the translations. for some reason, that guy and a few other missing assets is gone on versions 2 and 3.
a whole bunch of stuff i found is above, but basically you can copy that save i posted to version 1 and see that it works fine.
basically, anyone that's seeing this and wants to complete Vagina's 2nd quest (and see ending D) has to play the game on translation version 1 or move their save to that version.
You're perfectly fine if playing the 1.16 untranslated version though, which can't even use the translated saves. Otherwise, you have to wait til there's a working translation update that doesn't delete that guy by mistake
you're also locked out of the floor 10 and dragon (outside the city) bonus fights if you can't do this quest