HalluciGen Inc

When you enter the building, you'll hear an announcement that there's a chemical leak. The green fog in the building will cause all Gunner NPCs inside to go insane and attack each other.

From the reception area, go down the ramp then loot the duffel bag beside the lockers. Continue through the Hole in the Wall to reach a utility area. There are several containers here and a gas leak. Go past that room and go up the room and continue until you reach the next office. There's a Novice research terminal there where you can activate a suppressor prototype. This triggers the tesla trap in the next doorway. Beside that trap is an issue of Tesla Science so don't forget to pick it up. There's also a weapons workbench in the same room.

The next advanced-locked door only contains a trapped gunner with a handful of bullets and flamer fuel. In the next corridor, the path to the left will just bring you to the ramps you took earlier, the room next to that has a grenade bouquet trap and an ammo box behind the table. Across it is the security room with two inactive protectrons. Since the area is narrow, don't activate them unless you're having problems clearing the area. They can be activated using the Advanced terminal in the same room.

Continue forth and go upstairs. You'll find more enemies in the room to the left. Go through the door and to the next room. Here you'll find chambers with Glass roofs. You'll find more gunners inside fighting with each other. You can ignore them for now and continue upstairs to the next floor. If you enter the door to the left, you'll find the demo room. Here, you can try out the various chemical products on the gunners below by pressing the red buttons by the windows. In any case, these demos will kill the gunners below. The Advanced observation room terminal can also end the security lockdown.

Leave the observation room then continue forth. Take the ramp to the right then enter the CEO's room. Hack the Expert terminal to open the Master-locked safe nearby. Leave the room and take the next set of stairs to the west. You'll find a wounded Gunner Conscript in the base of the stairs. You can kill him if you want then loot his body.

Head to the next room where you'll find the lab access terminal. Before hacking it, enter the room to the left to find a gunner with a minigun. There's also a novice mainframe access terminal here. Select the option to reset the master password and you'll obtain the building's universal password. You can now use this conveniently to open the previously Expert-locked terminal outside.

Access the lab terminal and open the doors. You can't go through the gas so enter through the Hole in the Wall to the left instead. Access the decontamination terminal to remove the gas. Leave the room and continue to the lab where a Gunner Commander is waiting. Kill him and loot the Hallucigen Key, Hallucigen Mission Brief, Gunner's Note, and sturdy Combat Armor pieces from his body.

The room also has several chem stations, a Nuka-cola Quantum, a stealth boy in the open safe. You'll also find Hallucigen Gas Canisters here for Fred Allen in Goodneighbor's Hotel Rexford. Alternatively, you can create HalluciGen Gas Grenade using the gas canisters you have in your inventory. Continue ahead to find the green steamer trunk and exit.