A Meeting of the Minds

A Meeting of the Minds is a Fallout 3 main quest and achievement that is added to the game with the Point Lookout add-on.

Detailed walkthrough
After watching the Calvert Mansion explode, the Panic Room can be entered through a hatch in the ruins. There is some minor loot including ammunition and food, such as a Nuka-Cola Quantum and two very rare gum drops.

This mission begins slightly differently depending on who was sided with in Thought Control, either Desmond Lockheart or Professor Calvert. In either case, go to the Point Lookout Lighthouse where a section of the floor slides away. The final showdown takes place in St. Aubin medical facility, a secret underground lab.

Sided with Desmond
The player character installed the cogwave jammer and sided with Desmond.


 * Find Desmond. He is fuming inside the panic room about Calvert killing his dogs Freki and Geri.


 * Tell Desmond you are ready. Desmond has tracked down Calvert's signal to the lighthouse, in the underground lab, and is ready to end the 200 year-old feud.

' Note: This route makes Desmond essential until the final choice.

Sided with Calvert
The player character destroyed the cogwave jammer and sided with Calvert.


 * Travel to the lighthouse. Desmond is not inside the panic room but has already made his way to the underground lab in the lighthouse.


 * Desmond will confront the player character about destroying his jammer. Through dialogue, he can be told that you were tired of him being rude, or it was a trick to gain Calvert's trust or decide to kill Desmond at this point. If Desmond is not killed yet, he will assist in fighting the robots and the player will be able to make the final choice later on.

Making Your Way to the Brain
Once inside the lab, begin making the way down with Desmond, fighting Turrets and several Robobrains along the way. Desmond can be allowed to run ahead and engage first; if hit enough, he will become unconscious but will not die. If one has the Robotics Expert perk, then it is possible to deactivate the robobrains while they are distracted by Desmond.

The first room on the left from when entering the lab includes three first aid boxes and a Gatling Laser. In the next room directly downstairs, use the terminal to deactivate the turrets and pick up a Mesmetron Power Cell and Microfusion Cells.

In the next section, the first room on the left includes several types of energy weapon cells. The first room on the right is Dr. Stewart's office and includes an average safe with a Stealth Boy and other random loot, an ammo box with Microfusion Cells, and three Pre-War Books. The terminals in this room and those thereafter contain background notes on the lab. The last room before the stairs includes several more energy weapon and Mesmetron cells.

The stairs lead to a round room (also with Mesmetron cells) with two doors, one open. In the room on the right lies a Level Beta security badge for access to the next area. A robobrain sentry is stationed behind a locked door in this room that has the same badge. The next level down has operating rooms; the second room on the right houses a bunch of chems and another robobrain. It has the Level Beta security badge; a copy of it lies on a table in the corner. Use the terminal to unlock the door at the end of the hall. The next room has an easy safe with a Stealth Boy and a lot of Caps, as well as another Gatling laser and more energy weapons/ammo.

More stairs lead down to a hallway with several doors, all leading to bunks. Continue forward to eventually reach Calvert's room, where the Brain himself resides in a massive glass tank surrounded by inactive Protectrons and several apparently non-functioning Protectrons.

Who to kill?
If Desmond was not killed earlier, it is now time for the final choice. Desmond and Calvert will have a short, angry conversation, each of them claiming to have the Lone Wanderer's support. (Waiting too long, will cause the dialogue to loop). Eventually, a decision will have to be made of which one to kill. If spoken to, Calvert will offer the greatest thing any human could ever hope for in exchange for killing Desmond...

Killing Calvert
If siding with Desmond, shoot at the Brain's glass tank until the glass shatters or attack one of the docile Protectrons. (Desmond becomes temporarily essential until Calvert is completely dead.)

After the Brain is dead, any remaining robots will be disabled and Desmond can be spoken to. He will be overjoyed to have finally won and remarks that everything that Calvert stole from him is finally all his (although he's still a bit rude). Desmond gives the player character the exit key.

After speaking to Desmond again, he will say that after he's done in the lab he will go north to confront another one of the "players". He refers to this contest as a "microcosm of the old world". The option of killing Desmond is present but not mandatory.

Killing Desmond
If taking Calvert's side, simply shoot at Desmond or place a grenade in his pocket. (Calvert becomes temporarily essential until Desmond is completely dead.)

Once Desmond is dead, the Professor will offer his reward as the greatest thing any human could ever hope for... DEATH! At least he'll try, at which point he will activate some of the previously inactive Protectrons forcing the player character to destroy Calvert as well.

Rewards
In the sealed room, there are two ammunition boxes, a safe, two first aid boxes, some energy weapon ammunition, some misc. items, and the Microwave Emitter.

Bugs

 * The option to use the ladder in the panic room may remain on-screen after the player leaves the panic room. An easy fix is to simply look at something that would replace this text (i.e. looking at Desmond to force "Talk to Desmond" text to show up).
 * Sometimes when reaching the first locked security door in the lighthouse, if you choose to hack the terminal to get through (as opposed to finding the card), an invisible barrier may remain even after the door opens, preventing you from proceeding. This occasionally happens with others doors as well. To fix this, you can either save where you are then reload the save or exit the area and return, as well you can simply use the in-game command and you will be able to walk through the barrier, Desmond will simply teleport through (this can only be achieved in the PC version).
 * Some ammunition boxes, items and containers cannot be opened; they can be reached by using the console command through the floor.
 * It is possible that Desmond will run into the cupboard room when you open the first door after you meet up with him and then he doesn't move from there unless you proceed into the next area, where he still may not proceed with you.
 * If you destroy Calvert's jar with a frag mine, his brain may continue floating in the air.
 * It is possible to destroy Calvert's jar and leave his brain floating in the air on PS3 as well, although Sydney's 10mm "Ultra" SMG or a precision gatling laser were the weapons used to produce this result. In this instance, jumping into the brain caused it to dislodge from its spot and fall normally.
 * Destroying Calvert's jar may cause his brain to get stuck in the air. Jumping into the brain will cause it to dislodge and fall normally. (Weapon used to destroy the jar in this instance was a laser pistol.)
 * The animation of Calvert's jar may get stuck leaving it cracked and the game will consider him dead, but the dialogue between him and Desmond continues to go on.
 * Sometimes in the last circular room before the central room with Calvert, the game may glitch and force you to kill Desmond before the door will open to Calvert's chamber. During this time, if you talk to Desmond, he will have the same dialogue options he had after initially conversing with him, involving the tribals. Save, shoot him once to turn him hostile without killing him. Run in the circular room, he should follow and then the door will open. Once inside, go around to the left side until you can get to the brain. Destroy the brain. Desmond will then be friendly and talk to you about everything like normal.
 * You can kill Calvert with an explosion that knocks Desmond unconscious at the same time. (A row of bottlecap mines along the catwalk for example. It is important to set off the mine closest to Calvert first.) While Desmond is lying on the ground, he is unkillable, but you can shoot off his body parts. He stands up to initiate his dialogue as usual (voiceless if his head is missing) and then 'walks' away in his newly dismembered state.