If you’re looking to go after Harriet in Deathloop, you’re exclusively going to find her in Karl’s Bay. Unlike a handful of other Visionaries, she prefers to play by the rules, and because of that, she’s going to keep herself as far away from the others possible. So if you want to learn more and try to take her out, you’ll need to find a way into Hanger 2 in Karl’s Bay.
There are two known ways for you to enter this hanger. The most straightforward method is to go beneath the building, right underneath the pier, and crouch through a small entry point. You’ll be able to slip right into the hanger during Harriet’s sermon, so long as you’re visiting her during the morning. She’s not around the hanger at any other time of the day.
The downside to using that route is that the gas that Harriet fills the hanger with will come through here. You’ll be at the lowest point of the ventilation shaft, so it’s impossible to avoid being hurt by it.
The alternative way to sneak into Hanger 2 is to learn about the access point from Hanger 1. You can learn about it by scaling the back of Hanger 2. Go to the back of the hanger, and you should see a crate labeled ‘Otto’s’ on it. Scale the side of this, and follow the route up Hanger 2. Eventually, you’re going to reach the top, and you’ll find a window where you can peer into Hanger 2.
While you won’t be able to enter the hanger from this point, on the left side will be a table with a piece of paper on it where two Eternalists talk about making it over to Hanger 2 through a maintenance shaft in Hanger 1. It also comes with the code.
All you have to do now is make your way to Hanger 1, adjacent to Hanger 2, and go to the bottom floor. There’s going to be a door locked by a code, and you can use the code you’ve just learned to slip into Hanger 2.