End of Abyss Vault cleanup: plan the return trip
If you missed Vaults, first check how many Vault Keys you have and which optional bosses remain. Five keys come from story bosses; the remaining three require optional encounters, so do not search locked Vault doors without a key.
- Key or keycardOwn the named access item
- Power connectionTrace and destroy its node
- Explosive barrierReturn with explosive equipment
Count keys before retracing rooms
A player who had finished around 90% of the game said they skipped two Vaults because they did not want to backtrack for them. That is one player’s cleanup decision, not evidence that the locations are missable. Read the original discussion and comments before deciding whether the remaining reward is worth another trip.
| What you know | What it means | Next useful check |
|---|---|---|
| You have a Vault Key available | A locked Vault may now be worth revisiting. | Use your Scanner/map notes and sector + floor record to identify the door. |
| You have opened fewer than eight Vaults and still lack keys | The remaining keys are tied to optional boss encounters, not ordinary room exploration. | Check the optional-boss prerequisites before starting a broad return trip. |
| You are unsure which Vaults you already opened | The sources reviewed do not establish a numbered in-game Vault list. | Keep a personal checklist by sector and mark each opened door as you find it. |
| You want the Dungeon Crawler goal | Epic defines this achievement as opening all Vaults. | Separate Vault doors from the six-weapon, room-coverage and Logbook goals. |
The three optional encounters complete the key supply
The boss names and key split come from published guides, not a playthrough by this guide. Use the optional-boss overview for the reported prerequisites and route steps; confirm a specific room location against your game before committing supplies. The official achievement list is the source for the Dungeon Crawler goal.
- Finish the story route and note the Vault Keys you already have. Published guides report five keys from story bosses and three from optional bosses.
- Before hunting an optional boss, check its access tools and prerequisite route. The three encounters named in the reviewed guide are the Centipede rematch, Brood Keeper and Morgue Dweller.
- After each encounter, return only to Vaults you can now open. Mark the sector and floor in your own notes so you do not revisit the same locked door.
- When all Vaults are open, verify the achievement in the platform overlay; keep it separate from full Logbook, every-room and all-weapon goals.
Turn cleanup into one planned loop
Competitor walkthroughs make useful progress by separating the critical route from optional cleanup and by listing coverage boundaries. This guide uses that same decision pattern with your own save: put the map and backtracking checklist beside the return notebook and choose one target before leaving a shuttle.
A full Vault route with exact room directions is outside the facts verified here. For confirmed weapon destinations, use the six-weapon lookup; for the separate equipment and Logbook targets, use the completion checklist. A return trip can still cost supplies, so review save pods and death before treating another boss attempt as free.
| Before leaving the current area | Record this |
|---|---|
| Vault door you could not open | Sector, floor, and whether you had a Vault Key |
| Optional boss route | Named access tool still missing and the area where you saw it |
| Map or objective uncertainty | Current objective, last completed interaction, one next step |
| Supply-sensitive retry | Ammo or expendable kit you plan to spend, plus a workbench stop if needed |