This is part of McCready’s companion sidequest “Long Road Ahead”.
From the lobby, there’s a Novice door to the east which leads to some ammo. Go to the north then west to find an airlock chamber. You can’t do anything to it right now so follow the corridor east. Continue upstairs and take out more ghouls. Continue upstairs and follow the straightforward path until you reach the executive terminal. MacCready will give you the password. Use it on the terminal and override the lockdown.
Dropdown through the hole on the floor to reach the first floor. Now operate the airlock terminal and continue to the next area. In the next room, use the terminal to disable the turrets and open the security doors. Ghouls will come flooding in the area. There’s a chem station inside the room beside the security counter. Go upstairs and kill more ghouls along the way. There’s no need to open the containment cells by the elevator so just ride it to reach the sub-level.
Make your way to the east to find the cell block terminal there. You can use this to open the security doors, deactivate the turrets, and to activate the protectron. Behind it is an Advanced security gate with some loot behind it.
Head to the lower cell to the SE and go down the broken floor. When you reach the next room, pop the Fusion Core out of the generator. If you go upstairs to the room, you’ll find a Novice safe there. Continue east where the marker is pointing. Continue downstairs until you reach a containment room with a terminal by the door. Use the terminal to unlock the door then kill the remaining ghouls inside.
Pick up the Prevent drug on the lab counter in the middle of the room. This room also has a red steamer trunk. You can find another issue of the Massachusetts Surgical Journal on the table beside the radioactive reactor in the end of the room.