Kevin Spacey did not receive an Oscar nomination for portraying John Doe in Seven.
This first scene already has the imagery and the shock of the mysterious killer suddenly turning himself, but Spacey also brings far more than simply walking in on the scene. Spacey merely in his introduction presents something about his John Doe which defines his characterization of him. That is as he first walks into the police station Spacey speaks each attempt to get the detectives attention in this quiet unassuming voice until they repeatedly don't notice him, and then Spacey suddenly breaks that to a far cruder tone to finally get their attention. Once they see him though he returns to that quieter more eloquent speaking voice. This may seem minor, but it's something that Spacey uses to allude to something about John Doe, who of course is a character we know nothing about. More on that later. Much of the time though Spacey plays John Doe as though he is some other worldly man in the way he speaks with this certain detachment. Spacey is chilling in the way he realizes John Doe's mentality in this way he speaks about his crimes, which is not that of a series of extremely brutal murders, but rather to him is a message seemingly from the heaven itself, as though he is a man who is on a mission from God to do these things, in order for society to change.
Spacey is outstanding because of just how convincing he is in creating this mind of John as he explains his task with such a unpleasant grace as though what he is doing is a righteous act. Spacey exudes this sense of superiority of John, but not in quite the way that's usually case with Spacey playing a pompous character, which he does well. Here though Spacey brings this in this strange distance about it that it is not that John Doe is this excessively confident man, although he is in fact that, but rather Spacey presents it as a man who is so confident in his own perceived duty as though he is above all things. When John Doe indicates the purpose of his plan, Spacey makes it as though John is speaking of something profound. What is so off-putting is the way Spacey is able to illustrate John Doe's words not as just ravings of a mad man, though they are that, instead as a man with an absolute faith in his own moral code. This moral code involves extremely brutal murders, and Spacey is tremendous in the way the motivation for this is all in John's words. The murders in the film are not remotely practical, but rather would require an excessive amount of time and effort. Spacey makes them believable because is able to honestly portray John Doe as a man who would do these things.
Now this would be already a great performance if Spacey merely did what I've already written, but Spacey manages to give the character even more complexity, even within his limited screen time. Now back to his initial entrance where he was already that preacher of the word, except when he had to get the detectives attention. This comes back when Doe goes along with Mills and his older partner Somerset (Morgan Freeman) to supposedly find the bodies of his last two victims. Again it results from when John Doe does not believe his message is getting across, this time coming when Mills states to John that his victims were innocent. This sets Doe to describe each victims sins, but no longer as that man above the world. Spacey's presents very intense disgust and a vile sickness as John loses some of his composure in his descriptions, as though the idea of the people being innocent is more that Doe can stomach leaving him unable to stay as a the man with the purpose he believes is greater than himself. The humanity in Doe breaks out in this moment, as Spacey alludes to perhaps whoever it was the man who became John Doe, a man with such a hatred towards the worst in society. I love this moment in Spacey's performance because he so naturally realizes that Doe is not something from heaven or hell, but still a man inside his "better" self. The new self is not an act, though Spacey reveals what came before, as what came before is what created John's current state. Spacey does outstanding work here as he creates such a compelling force of a man with John Doe in these few scenes, while managing to make the crimes and most pivotal the final act of his plan conceivable. When it is revealed what John Doe wants in the end, it only seems logical as Spacey has so effectively made sense out of the man's twisted mind. In just a few scenes Spacey creates an unforgettable villain, that lives up to his build up and reputation beforehand, giving an amazing performance essential to the success of the film.