Spoilers, obviously.
In the finale, we get the back and forth comedy argument between Seth Milchick (Tramell Tillman) and an animatronic Kier Eagan (voice of Marc Geller, animatronics by Ben Stiller).
I'll quote the exchange below:
Kier: Hail your earthbound steward, your very own flooooooooooor manager!
[audience cheering]
Milchick: Thank you, Kier! And may I say, you're looking very handsome, sir.
Kier: Thank you. I'd say the same of you, if not for my favorite core principle.
Milchick: Probity?
Kier: No ... Vision!
[audience laughter]
Milchick: Well, it's truly special to host a man so illustrious, so sapient, so magnanimous--
Kier: My, you're verbose. Good thing you didn't write the first appendix. It would have burst!
[audience laughter, Milchick visibly discomfited]
Milchick: It's an honor to receive your barbs, Mr. Eagan. The legacy you've left behind is truly and irrefutably larger than life.
Kier: You mean my company?
Milchick: (coldly) No. I mean this wax statue that's five inches taller than you actually were.
[audience chuckles, awkward silence]
Kier: (darkly) Thank you for that feedback, Seth.
Milchick: Thank you, Kier.
This is clearly a prepared routine. It has setups and punchlines and Milchick is visibly reading most of his lines from note cards. However, the performance obviously goes some way off the rails in the back half.
Who wrote this routine? Who performed Kier's lines in-universe? Has Milchick rehearsed this routine or does he only know his own note cards? Is Milchick's height roast part of the script or improvised?
I'll post my thoughts in a separate comment.
The most obvious part, both halves of the routine seems like they were most likely scripted by Mr. Drummond. The barb about Milchick's use of language is something very specific to Drummond's relationship with Milchick, and Milchick's half of the dialog is deliberately written to set up that joke. The appendix line is clearly a previously-written corny punchline and not improvised.
The Kier animatronic appears to be performed live by somebody. It responds emotionally to Milchick rather than being a series of obviously recorded lines for Milchick to work around. This opens up the possibility that Drummond is also playing the vocal role of Kier, presumably via voice changing tech, but at that point it could be anybody--whether that means a character we know or not, although they do seem to know Milchick personally.
In the real world, Marc Geller (IMDb) is the actor who plays Kier physically and in voice lines, but the actual character is almost certainly long dead by the time of the show, barring any Walt Disney shenanigans. No doubt, Lumon finds it useful to be able to simulate the authoritative voice of their founder for propaganda purposes.
I lean toward Milchick not being made aware of what Kier would say ahead of time. He has his own lines, but I don't think he knows the founder is about to roast his use of language. That seems to have been a surprise thrown in to upset and humiliate Milchick in front of his staff. If he already knew this line was coming and/or had rehearsed it previously, I don't think he would have reacted so strongly.
I do think Milchick's height gag is scripted. There's too much setup with the "larger than life" line preceding it for it to have happened organically. However, I think Milchick spits the line with 1000% more venom than he was supposed to, in retribution for the previous gag at his expense. If you read Milchick's line in a good-natured way, it sounds like perfectly reasonable, toothless corporate comedy. Milchick just imbues it with a power that Drummond(?) never intended it to have.
Kier's final line, "Thank you for that feedback, Seth," is the only one that I think is wholly off-book. Whoever is on the other end of that animatronic is clearly displeased with Milchick's delivery.
I feel like there's a connection to the 'board' and how the building was personified in that animation in S02 E02. Not a straight up artificial intelligence, but maybe a 50s version?
- Kier Eagan
That's an interesting observation about the Board. The Kier voice seems similar to the Board voice we briefly heard from the intercom in S1.