Et Tumor, Brute?

Et Tumor, Brute? is a main quest in Fallout: New Vegas.

Synopsis
Caesar has been experiencing intense headaches and blackouts more frequently as of late and asks for diagnosis and treatment of his ailment.

Detailed walkthrough
After wiping out the Brotherhood of Steel as part of the Render Unto Caesar quest, Caesar asks the Courier to meet him in his tent privately. Caesar explains that he has been suffering from debilitating headaches, his left leg has been dragging, the Courier has noticed him blank out, and that Lucius has said that he stares into space. The player character can properly diagnose him through either a 50 Medicine or 60 Speech check followed by 75 Medicine and 65 Speech checks. Caesar asks them to gather the proper tools and hurry back or asks who can help him if the first Medicine check or the Speech checks were failed, initiating the quest. Whether the player character passes the skill checks or not, they can ask about the Auto-Doc in his tent. Caesar explains that it is missing its diagnostic scanning module and that one may be found in Vault 34. If Arcade is a current companion he can also be offered immediately into slavery as Caesar's personal physician, skipping the quest but making him permanently unavailable for recruiting.

If Caesar's 50 Medicine check or 60 and 65 Speech checks were passed, then it is possible to use a set of surgical tools and a doctor's bag for the operation. The surgical tools can be bought from Dr. Usanagi at the New Vegas medical clinic for 999 caps or stolen from a first aid box on a stretcher in the adjacent room. If the skill checks were failed then neither the surgical tools nor the first aid box will spawn, and any option involving performing the surgery alone will not be available.

The diagnostic scanning module Caesar refers to is the automatic surgical unit. It can be found in the clinic room of Vault 34, located northwest of Camp Golf and east of NCR sharecropper farms. When first walking into Vault 34, take the first right to the stairway that will lead to the cafeteria. Drop down the hole in the floor, exit the room, and turn left. Follow the corridor and the signs for "clinic". The Auto-Doc is on the back wall. Interact with it and the option to take the item will appear.

Upon gathering either the surgical tools or the automatic surgical unit and returning to the Fort, Caesar is in a coma and is near death. Only an operation to remove the tumor from his brain will save him. There are several options to finish this quest:


 * 1) Use the surgical tools in conjunction with a doctor's bag. The operation will only be successful if the Courier has 75 or higher Medicine skill, otherwise, Caesar will die.
 * 2) Trust in one's luck and perform the operation. Having the above items and 9 Luck is required for the option to be shown and the operation will always be successful.
 * 3) Install the automatic surgical unit into the Mark III Auto-Doc in Caesar's Tent. After installation, one can choose to activate the surgery mode to successfully remove Caesar's tumor or activate autopsy mode, which causes his head to explode, killing him.
 * 4) If the first opportunity to sell Arcade into slavery was passed on, it is still possible to sell him later to Lucius. The screen will fade to black, and when the scene resumes, Caesar will be cured. This is not possible on PC due to a game breaking bug (see Bugs).
 * 5) Arrange for Caesar to die during the surgery.

If Caesar lives, he will thank the Courier for saving his life, and will then move on to give the Arizona Killer quest.

If Caesar dies, Lucius will confront the Courier and accuse them of killing him. With a Liked or higher reputation or passing either a Medicine 50 or Speech 50 check, it is possible to convince Lucius otherwise and remain friendly with the Legion, or else they will become immediately hostile.

Behind the scenes

 * The title of this quest is a play on Julius Caesar's famous last words, "Et tu, Brute?" from the Shakespearian play Julius Caesar which translates to "And you, Brutus?," showing Caesar's dismay in seeing Brutus taking part in his assassination and betrayal.
 * The quest is an elaborate allusion to Julius Caesar, who did indeed suffer from an ailment that caused severe headaches and was also a secret from the public. Caesar's headaches were more likely to have been caused by a motor function disorder, causing him to fall regularly ("falling sickness"). Other theories on this include epilepsy, migraines, and even malaria.
 * If after Arcade is given as a slave the player character speaks to him and says "The world needs Caesar more than it needs you" Arcade will respond "Victrix causa diis placuit sed victa Catoni" which can be translated as "the victorious cause pleased the gods, but the conquered [cause] pleased Cato." This is a quote from the Latin poem Pharsalia by Lucan, in which the historical figure of Caesar is portrayed as the main antagonist, and the main hero, the historical figure of Cato Uticensis, is eventually forced to commit suicide, being unable to defeat Caesar.

Bugs
Completing the quest via offering Arcade Gannon to Lucius causes a show-stopping bug whereby Caesar is not woken from his coma and is permanently stuck. Only his coma message box will show when interacting with him even though that quest is marked complete. The reason is a developer omission of 3 lines of scripting for that specific quest outcome.