This machine: the song, the lyrics, the instruments, and everything involved in the recording and playing of this song cannot possibly communicate his true depth of his feeling (e.g., anxiety, stress, sadness, etc) about the hopelessness of our inevitable, and pending, death that awaits everyone.

It’s almost like our bodies themselves freak out because they can’t understand that feeling

“This machine will not communicate” could reference how we have a very hard time handling the “feeling” of what being dead might feel like. For some people, it can give them something that feels like a panic attack.

Regarding “all these things” and their potential resolution (“swallow whole/and fade out”), compare this dialogue from The Famished Road where a spirit reveals the road between worlds (which is without end and leads everywhere):

‘Are we travelling this road to the end?’
‘Yes,’ the spirit said, walking as if distance meant nothing.
‘But you said the road has no end.’
‘That’s true,’ said the spirit.
‘How can it be true?’
‘From a certain point of view the universe seems to be composed of paradoxes. But everything resolves. That is the function of contradiction.’
‘I don’t understand.’
‘When you can see everything from every imaginable point of view you might begin to understand.’
‘Can you?’
‘No.’

The correct lyric is “all these things you’ll one day swallow whole.” That’s YOU’LL, rather than “we’ll” and, more importantly, the line ends with with “swallow WHOLE.” It’s easy to miss the “whole,” when listening, because of Yorke’s vocal delivery, but his discussions of the song, and these specific lines, make it crystal clear.

I like a hybrid of the two ideas. In a depressive state, sometimes the shadows are nice and quiet. Those times are night when you are alone in the dark might be all the time you get to reflect. But maybe Thom is the shadow figure at the end of the bed people always see during sleep paralysis. Maybe too much of a stretch, but maybe the shadow paralysis figure is paralyzed to move too.

Verse 3 is written from Kid A’s perspective.

In a combination of both of these theories, Kid A has just awakened from some kind of emotional “slumber” where they had visions of evil watching them as they slept. Throughout the entire album, Thom references a malignant, puppeteering conglomerate of evils that control and haunt the masses.

Also, the precluding lines infer a back and forth dialogue that is possibly held between Kid A in their bed, and the shadows lurking at the end, as the shadows attempt to strike a deal:

“You’ve got heads on sticks
We’ve got ventriloquists…”

A comparison is made between children and vermin as rats are known to carry disease.

It’s important to note that however “Kid A” is ultimately interpreted in its exact narrative, the audience is following a character ambiguously named as the first of their kind to explore this new world.

As it is the titular track, one can assume the lyrics are written from the perspective of Kid A, as they emerge from their hiatus and become some form of a leader as they continue forward in this alien place.

I also firmly believe that this line is reference to the Beatles themselves since the white album sessions were, despite their brilliance, the beginning of the end for the group. Harrison used a similar sense of duality in his song, “Isn’t it a Pity” later on…

I have always taken it as, Lennon’s dream was to be a famous musician, but his self doubt left him questioning if he was wasting his life by believing it’ll happen. And how he used to comfort himself and what he believed was that he was smart enough to know if his dream really had a chance

Also it’s a trick of his to say he knows when he’s on a trip (I know when it’s a dream) but he doesn’t always know when he’s sober. A classic “how can he?” line.

I would say the Beatles were incredibly lazy lyricists – at least in the early days. E.g., the chorus of this song: “I’ll get you, I’ll get you in the end/Yes I will, I’ll get you in the end/Oh yeah, oh yeah.” (Lennon-McCartney songwriting rule #1: when you run out of things to say, throw in a couple of “Oh yeahs.”) Females went crazy over the Beatles in the Beatlemania period because their typical fan was 13 years old and susceptible to mass hysteria.