Help to understand the structure: why before the needles returned, shredding my thoughts

Question

I AWOKE WITH NEEDLES in my brain. Thousands of them, biting, blocking out everything. Then they disappeared for one dizzying moment and I got my bearings. It was morning, early; amber sunlight poured in through my bedroom window. I was standing but not on my own strength. Two hands were gripping my throat, and they’d been shaking me. The needles, that was my brain crashing into my skull. I had only a few seconds to wonder why before the needles returned, shredding my thoughts. My eyes were open but I saw only white flashes. A few sounds made it through to me. “SLUT!” “WHORE!” Then another sound. Mother. She was crying. “Stop! You’re killing her! Stop!”

I copied this text from another question. The part I don't understand is the structure of why before the needles returned, shredding my thoughts. Since I am pretty interested in it, I'd like to ask it as a separate question. Thanks!

Answer 1

Let's break it down.

First the expression, I wonder why, which is used to phrase certain kinds of questions.

I wonder why the sky is blue?

or in a narrative:

I wondered why they were all shouting -- then I saw the runaway bull heading right at me.

or, in a different way, adding an adverbial clause to establish the time frame.

I had only a few seconds to wonder why they were all shouting, before I saw the runaway bull heading right at me.

In your example, the main part of the sentence is:

I had only a few moments to wonder why (some situation was happening)*

followed by a similar adverbial phrase

before the needles returned (and did something)

I'm not sure what part of speech "shredding my thoughts" is called. Possibly it's a kind of participle phrase modifying "needles", but it seems more like the comma serves as an informal conjunction between the action of returning and the action of shredding.

Here is a more typical example of a participle phrase:

A moment later the bull reared up, snorting like an old locomotive.

Anyway, hope this helps!

Answer 2

As already stated by @user3169, you have not splitted the sentence correctly.

It's not

I had only a few seconds to wonder why before the needles returned, shredding my thoughts

It's

I had only a few seconds to wonder why before the needles returned, shredding my thoughts

According to Cambridge Dictionary

to wonder

to ask yourself questions or express a wish to know about something

In your context, she awoke abruptly and she wondered

why does my head ache so bad?

why is my brother beating the crap out of me?

...

She was wondering such things and then suddenly the needles returned. As explained here, "needles" is a metaphor for a kind of pain. She stopped wondering because probably she was being hit again.