Speak with Emily in the Board Room to get this side mission.
Locate Dr Underhill below Central Research
Fast travel to Central Research and look for the elevator shaft on the ground floor, at the end of an overgrown corridor with a yellow light at the end. Use Levitate at the bottom to ensure you don't fall to your death, then proceed through the doors to find Dr Underhill in her lab.
Collect five Mold samples for Dr Underhill
There's five types of Mold you need to collect for Dr Underhill, and we'll go through the locations in order. Leave her office via the other door, then go up the stairs and through the next door to enter the location of all the Mold samples.
Type A: Corpses
Cross to the other side of the area and go up the stairs, into where the Control Point is. At the very back of the room is another smaller, lighter room with this Mold sample in.
Type B: Toilets
In the top right corner from where you enter this area is a large entrance, with a sign for the restrooms next to it. Go to the end, then when it opens up, look to the left for a ledge to climb. You'll find this Mold up there.
Type C: Televisions
Keep following the path past the toilets and you'll eventually reach a small room with some televisions in, and this sample of Mold.
Type D: Staircases
You know the stairs you went up to find the Control Point and Type A? Type D is underneath them.
Type E: The Pit
In the middle of the main room is where you'll find the final sample, by a desk at the bottom.
Investigate the Pit
Head into the enormous pit with the purple glow and use Levitate to stop yourself from falling to your death again. Get ready for another boss fight, because this time you're up against Mold-1. It's a huge, three-eyed tentacle monster made of Mold, and this fight is the most traditional boss encounter you'll face all game. Mold-1 will lunge at you with any of it's three eyes, along with sending out homing missiles made of Mold to take you out if you're behind cover.
With that said, this fight isn't too difficult. If the homing missiles are after you, keep using Evade to dash in one direction and escape them, and make sure you're using the Pierce weapon mod so you can deal immense damage as soon as it stops covering the eyes. Launch can be a great secondary attack if your weapon is reloading too.
Main Missions:
Control walkthrough: Welcome to the Oldest House
Control walkthrough: Unknown Caller
Control walkthrough: Directorial Override
Control walkthrough: Old Boys' Club
Control walkthrough: Threshold
Control walkthrough: My Brother's Keeper
Control walkthrough: The Face of the Enemy
Control walkthrough: Finnish Tango
Control walkthrough: Polaris
Control walkthrough: Take Control
Side Missions:
Control walkthrough: Old Friends
Control walkthrough: Fridge Duty
Control walkthrough: Self-Reflection
Control walkthrough: Mr Tommasi
Control walkthrough: Old Growth
Control walkthrough: A Matter of Time
Control walkthrough: Langston's Runaways
Control walkthrough: The Enemy Within
Control walkthrough: Mold Removal
Control walkthrough: What a Mess (all missions)
