Fallout 4 created by Bethesda Game Studios.
Images used for educational purposes only.

Prerequisites: Complete Here Kitty, Kitty
Trigger: See below
Reward: Varies; see below - always get 300 XP

- Hole in the Wall has a slightly tricky trigger. There are two conditions: first, you must complete Here Kitty, Kitty for a little girl in Vault 81, and second, you must have given blood at Vault 81’s clinic. Leave for a while and come back and you’ll find the quest’s participants busy in the clinic. There’s a good chance you can screw up the trigger for this quest by not doing Here Kitty, Kitty properly, so follow this walkthrough to the letter.

- Upon entering the clinic you’ll discover that Austin, the little tour guide boy, has been bitten by a Mole Rat. You’ll learn of a secret Vault adjoining Vault 81. Follow Bobby out of the room and he’ll lead you to the reactor, opening a secret door for you upon arrival. Head inside.

Secret Vault 81. This place is a nightmare
if you want to avoid getting bitten.
Secret Vault 81

Before we get started, a word of caution: something bad will happen at the end of this quest if you are successfully attacked by any of the Mole Rats that appear in this area. If you want to avoid that happening, you just need to not get hit. Sounds fun, right? Explosives, stealth movements, a silenced weapon, and a lack of companions will make this area much easier, assuming you want to avoid this grisly, heretofore ambiguous fate.

- You emerge in a Vault that has obviously seen better days. Ahead and on your right is a small side room with a bunch of fairly useless junk; straight ahead are stairs. Up! Your first Vault 81 Lab Mole Rat is hidden at the top, in a dirt pile. Be ready with V.A.T.S. to take it down.

- Take a left at the stairs. There are some Stimpaks in a niche on your left, and at the end of the catwalk is a small room. There’s a terminal inside that explains some of what happened here. The next door leads into a hallway; be ready for two ceiling Turrets to open fire when you round the corner to the left. Attacking them will also draw a Protectron out to battle you.

- Down the hall you’ll find a room on your left joined to another room, allowing you to bypass the blockade in the hall. Beyond are stairs leading down to a cafeteria, and when you get to the bottom another Turret to your left will open fire. Take it out. The cafeteria and the bathroom beside it are fairly useless, so head down the hall next to the Protectron unit in the pod.

- Keep walking until you reach a dirt floor. This is danger territory. The dirt itself is fine until you reach the stairs at the far end, at which point multiple Mole Rats will burst out of the ground behind you. Crouch, move up the stairs a bit, and use V.A.T.S. to kill ‘em. They have frail bodies, so one hit apiece should do.

- Check around at the top of the stairs for several Stimpaks in boxes, then approach the monitor near the next set of stairs. It reveals some of the true purpose of this hidden Vault. Continue up the stairs to find a security door; you’ll hear Mole Rat noises, more than likely, but none will appear.

- There’s another monitor in the next hallway, and looking at it or moving past it will trigger a slew of Mole Rats to spawn in several different places, most of them back the way you came. Be ready for the little bastards to try and rush you from behind and bite you in the butt when you’re not looking. Quick V.A.T.S. work will keep you safe. More will start pouring through a gate near the next terminal down the hallway; stand a distance away and peg them as they burst through.

- Head down the stairs past the gate. There’s some ammo in a spilled locker on your right and a door on your next left, beyond which you should hear Mole Rats bursting out of the ground like crazy. This will be borne out a bit in the next area, a two-level concourse, as two Mole Rats will charge out of a room on your left, and another from the room on your right. Take ‘em down. There’s a Master wall safe in the right room, if you have the chops to get it open. (Note that a Mole Rat on the upper level may clip through the floor in these rooms; feel free to shoot ‘em in the face while they’re jutting out of the ceiling.)

- Head to the upper floor. On your right is an Expert door to hack open. If you can’t open it yourself you’ll have to walk to the rooms at the far end of the floor, where a Mole Rat Brood Mother waits. Getting into a battle with it will bring another Brood Mother out to play, along with a ‘normal’ Mole Rat that takes a lot more damage to kill, for some reason. These Mole Rats spawn to your left and behind you, making them extremely dangerous. If you fear being bit, consider jumping off of the platform and onto the lower level so you can kill them on the stairs. 

- You’ll find a trunk containing some goodies in one room in the section they were guarding, as well as a Mini Nuke in a fallen locker. There’s another terminal in the larger, adjoining room - and, beside it, a Vault 81 Tech Password Holotape. There are number of other items in this room worth collecting, as well, including a Stealth Boy on one of the tables. Note, too, that the fridge in this room actually has stuff in it, unlike 99 percent of fridges in Fallout 4.

Curie, the most adorable robotic nurse evar.
- Use hacking or the Password to get through the door. Inside you’ll find a sealed room ‘manned’ by Curie, a Miss Nanny robot. She has created a Vault 81 Cure over the years, and after you ‘authorize’ her to leave her room she’ll hand it over to you. Check her room for two more terminals and a Medicine Bobblehead, sitting beside the terminal on the desk. Use the elevator outside Curie’s room to return to Vault 81.

- Head back to the clinic. The doctor is waiting, and he’ll ask for the Cure. You now have a choice: 
  • Keep it for yourself. You'll have a second chance to go back on this decision, but if you stick to your guns Vault 81 will basically hate you. If you use the Cure on yourself things will carry on as normal, with no problems stemming from any Mole Rat bites. Any companions you brought along will, typically, think you are the scum of the earth for going this route, so you may want to give them the boot before making the decision.
  • Hand over the Cure. This will delight the people of Vault 81, as opposed to making them hate your guts, and the doctor will give you a Short Syringer Rifle as thanks. The Overseer will also give you a room of your own. (It’s the former storage room on the upper floor of the atrium when you first come out of the elevator from the surface.) On the flip side, you will permanently lose ten health if you were bitten and didn't cure yourself. Yay! Hope you were careful!
- Head out after the quest. Curie will stop you and ask to become a companion. Let her tag along and you’ll have another flaily robot like Codsworth, only with a French accent. Glee! Curie is incredibly useful, as she'll periodically give you a Stimpak if you speak to her. Few things are as handy as Stimpaks.