After you have infiltrated the tower, you will find that you have several options for killing the Lord Regent. You can either remove him from his throne using peaceful means, or take him out with blade and magic. Head to the Lord Regent's room in the back of the hall and hack his safe using the combination 935. Proceed deeper into the castle to explore, find new collectibles and more enemies ahead.

You will next encounter the 'Kill the Torturer' side mission. This will negate a Clean Hands playthrough, so be careful if you're looking to get no kills and skip this one entirely. Move through the door to the right of the hall and follow the stairs dwn to the torture room. The torturer will use Outsider Magic to pull you in; kill him however you choose when you get close. Be sure to loot the Outsider Shrine for a Rune.

Next, head up to the second floor. Along the way, grab the Small Scale Combustion Refinement blueprints from General Tobias office. They're on his desk. On the way up, use Blink to hide on the chandaliers overhead. Make your way across the room and to the Lord Regent's bedroom, where you will find a Rune in the footchest. Explore the room and you'll find a Bone Charm behind the fireplace. Turn the brass candle fitting to spin the fireplace around and loot the room behind it. You'll also find a message for Emily.

Proceed up to the roof next. You can get there via a narrow flight of stairs next to the piano. On the way up, use Dark Vision to highlight the Sokolov Painting by the piano and take it. When you get to the roof, loot the safe room for a fourth Rune. It'll be guarded by a Tallboy, so watch out.

You can now choose how to deal with Burrows. You can either kill him yourself, which will require you to follow the objective marker into the safe room to finish the job, or you can speak with the radio operator to sabotage Burrows' poiltical carreer. Whichever you choose, head back to Sam on the boat to finish out the mission.