Depending on who you chose to look for at the end of the first episode will decide who you find, if you chose Ellegaard then in episode 2 you will be looking for her, who is the Engineer. Completing chapter two will unlock this.
You can rewind episode 1 to change who you choose by pressing
or you can press
to choose a new save file, start episode 2 and hope that the random choices pick the other person for you.
(The episode will start with Olivia, details on what to do in chapter 1 here
Solution for Nether Say Die In Minecraft: Story Mode - A Telltale Games Series (Windows))
In order to acquire the Engineer you will firstly need to get a repeater, get one from the Disco man, to do this I first talked to the school boy with the large walking creation, I asked him for a spare repeater and he then directed me to the disco man, I asked him for a repeater and then went through all his conversational choices. He then went over to argue with the schoolboy, whilst they were arguing I stole his repeater which was far right next to his machine. I then walked back over to Oliva (far left at the back) and placed the repeater next to her and turned the 1st and 3rd switch forward to get inside.
Walk through the doorway which will open once you trigger the pressure plates, you will have to change the timing on the repeater to get through the squashing mechanism. Walk up and pull the lever to make it through the lava wall.
Pull the lever next to the 'zipper' and walk into it.
You will now be with Ellegaard, press
to talk to her and complete the conversational options then press the button on the left to activate the circuit, then grab what she asked for and pick them up from the chest on the other side of the room.
There will be some more conversational choices here and I chose to help her make another block so I has some more QTEs to follow but I don't think it matters what you choose, after this the monster will attack and you need to press
to grab her.
Time for more QTEs on your way to the portal and once you're through the portal the achievement is yours.