A fatal floor
What can "a fatal floor" possibly mean?

Context:
I heard it in a comedy sketch from "A Bit of Fry & Laurie" (the one about grotesquely pretentious critics), and there is a following dialogue there (from 1:56; https://www.youtube.com/watch?v=CHtjl8V483A):

- Martin, limp thoughts?
- None whatsoever.
- I thought not. Care to make some up for me?
- Well, this chair is soft, certainly.
- Very soft?
- No, no, it falls short of being very soft. But, of course, if you look underneath we find...
- The floor.
- The floor, precisely.
- Does the floor work for you?
- No, it doesn't work, it doesn't work. The floor doesn't work for me, no, no.
- No.
- Is it a fatal floor?
- Well, precisely. You see, the reason the floor doesn't work is 'cause it's all on one level. And, of course, it also falls into the trap of being essentially self-referential.I feel there must be a wordplay here, but I could't find the meaning of "a fatal floor" (according to Google, there is a very (!) strange British information film, but that is all). I thought that maybe it's not a "floor", but I checked the script and the subtitles, and it is. Could somebody help me figure it out, please?

Question

A fatal floor
What can "a fatal floor" possibly mean?

Context:
I heard it in a comedy sketch from "A Bit of Fry & Laurie" (the one about grotesquely pretentious critics), and there is a following dialogue there (from 1:56; https://www.youtube.com/watch?v=CHtjl8V483A):

- Martin, limp thoughts? 
- None whatsoever.
- I thought not. Care to make some up for me? 
- Well, this chair is soft, certainly.
- Very soft? 
- No, no, it falls short of being very soft. But, of course, if you look underneath we find...
- The floor.
- The floor, precisely.
- Does the floor work for you? 
- No, it doesn't work, it doesn't work. The floor doesn't work for me, no, no.
- No.
- Is it a fatal floor? 
- Well, precisely. You see, the reason the floor doesn't work is 'cause it's all on one level. And, of course, it also falls into the trap of being essentially self-referential.I feel there must be a wordplay here, but I could't find the meaning of "a fatal floor" (according to Google, there is a very (!) strange British information film, but that is all). I thought that maybe it's not a "floor", but I checked the script and the subtitles, and it is. Could somebody help me figure it out, please?

Answer

It is a play on words  - something that is fatal will kill you.
He is sarcastically asking if the floor is dangerous....however we also use the term fatal flaw - which sounds very similar to fatal floor - this ma be the play on words - depending on their accents

flaw - being a weakness, error, mark, or blemish in something e.g there is a flaw in the material of this shirt - there is a flaw in the design of the house

Hope this helps
Jane :)

Answer

Yes, I think Jane is right.  I listened to the clip and it's a play on "fatal flaw" -- with the floor's fatal flaw being that "it's all on one level."  Really a funny send up of critics.

Answer

Thank you very much, Su.Ki! It wasn't "needless to say" at all :) It's all very interesting, actually, so thanks for the insight.

Answer

Needless to say, this pun only works in certain accents. "Floor" and "flaw" are homophones for most people in England, and most English people who've studied literature would immediately get the joke. The critics  have nothing to say, so they've resorted to talking about the furniture using the pretentious language of literary criticism. The pun fatal flaw/floor highlights the  contrast between the banality of the subject and the pretentiousness of their  conversation. This wordplay is amusing for anyone with a non-rhotic accent. Less so for Scots, Irish and North Americans, I would imagine.