At the start of the game, as you walk through the detention area, you will come across Benjamin Burke, an inmate who trapped his cell. The door is partially open, but you will be too weak to move it any further.
How to free Benjamin Burke
Cross the podium to get to the central surveillance area and open the door. Head to the arsenal and take out the enemy found. You will need to attack the head by fixing it with your right thumb and then patting it until you aim at their head.
When they have come down, go to the room they came from and settle in with your device at the Med Bay. When you are all installed, leave the room and take out the new enemy. Pick up their weapon, making sure to cut off the arm holding it back.
You can do this by targeting the arm the same way you did the head and pressing the button with prompt when their health is low enough. This action cuts off the arm, allowing you to pick up the weapon.
Return to the surveillance center, but beware. There is a new enemy between you and Benjamin Burke's cell, and he can hit hard. Take it out, cut off the arm if you want the weapon, then open the cell doors.
Fully exhaust all of Benjamin's conversation options, then descend into the main room. There will be human enemies here, take them out and head to the door to collect the item. You can now return to the locker room of the armory and continue through the area.
It's a good idea to save Benjamin, because when you find him later in the game, he'll give you 20 Tech Scrap for freeing him.